[Islandcanine]

Is there any way of finding out what diet the dog was on before you acquired him/her?
Know that finicky eaters are not born, they are made.
It will be up to you to find out what your dog likes to eat and what he will eat.
What works for one dog may not work for another.

Chances are your dog really isn't interested.
Chances are too, that this dog was fed table scrapes or he was cooked for.

The First Thing That You Need To Do
Cut Out All Treats. If you do treat him, make sure it is All 100% protein. Cut out the junk food snacks.. Bacon strips, milk bone etc. 100% protein or nothing at all. Read the ingredients on those snack packages. Do you know what All the ingredients are? If not, don't feed it to your dog. 9 out of 10 it is loaded with chemical preservatives, sugars and fillers. Synthetic ingredients. Do not feed you dog junk food.
Especially if he exhibits finicky eating.

Second thing you Must Do Immediately is Stop feeding him at the table. Stop Stop Stop. Do Not Feed The Dog By Dropping Food From the Table When You Are Eating, even if it is Kibble. Do Not Do this!! The dog will develope bad manners for one and for two you do not want him in this habit. You want him to eat his food at his place on the floor out of his dish or off his plate.
My Dog wont eat out of a bowl. It has to be a plate or else she just wont eat.
Also I have found that If I move her dish she will eat, when prior she show dis interests. Especially when we are out of town. I put her dish down and she wont eat. I pick up the dish and put it to another part of the room and she is fine. Before it was that she wanted a safe place to eat where no one could get to her from either side or behind (She was in day cares for weeks at a time prior to my getting her) Now she just likes to eat near me. So at home, when I feed her, in the kitchen, I am right there doing the dishes until she finishes eating.

Don't free feed (leave food out for him to eat when he wants).
Have set feeding times and stick to them. IE: Breakfast around here is 8-8:30, Dinner time is always 5:30.
Most Important: Walk before you feed. Get into this habit and he will soon fall into the routine.
When you get back from a walk and are preparing his meal, have him with you and tell him to sit and stay. Do not let him wander around doing what he wants. Discipline him to sit and hold, making him wait until his meal is prepared.
Exercise, discipline and reward(food) is the key to a well rounded dog, in my opinion.

If you look on the back of the bag of dog food, it will tell you how much is recommended to feed him per day.

Sometimes, when my dog doesn't appear to be interested in her kibble we play a game. I start with playing with her with her toys and then we go to the kitchen. I ask her if she is ready, while I am crouched down at some kibble on the floor. Once she is in position and waiting, I flick the food and she chases it, making a game out of her food. She eats it. We can play this game for 10-15 minutes, in which time I can get her to eat at least two to three tablespoons of kibble.

My dog happens to be a Yorkie X with Maltese as well with a bit of (apparently but don't see it) s**tz Tzu as well.
If you may be so inclined, perhaps do a Google search for breed specific diets.
My dog can be finicky as well but I make the times rigid and am firm when I tell her to eat. If she walks away and clearly isn't interested, I don't force her to eat but I will try to persuade her, knowing she must eat if say she only ate breakfast and it is now 5:30pm.

For my dog, since she is 6 pounds, I make sure that she doesn't over eat but assure that she is getting enough food per day as per her weight and activity level.

One last thing, sometimes I take a very small amount of whole milk plain yogurt that has active bacteria in the ingredients and add it to the mix. Only a tiny bit though; a couple tsp's at the most.

You could test to see if he likes yogurt by putting some on your finger and letting him lick it. If he shows interest, you could try mixing some with his kibble.
He may like it a lot.

Do not over due it though. Only once a day. If you want to use yogurt on his food for all his feeding times, split up the small portion of yogurt.

What kibble are you feeding him?

Like yourself, when I introduced my dog to kibble, she would eat it for one maybe two days and then nothing. When I got her on the latest kibble, I came home and opened the bag. We played the kitchen game with it first off and she ate it. She likes it too. Still eats it!

Another thing is the size of the kibble. Try to find a decent high quality kibble that comes in small bites. Sometimes even if the kibbles are relatively small they are hard as rocks and makes for an unpleasant experience trying to eat them.

How are your dogs teeth? maybe he has an issue inside his mouth. My dog did when I got her, as a rescue at 15mnths old. Her teeth were so yellow her gums hurt and wouldn't eat kibble at all. It hurt too much. I have since had her teeth scaled and we brush everyday.
Important!
Especially if you feed your dog wet food too!

I would cut the dog some slack for right now since he is new and his surroundings are new but I would encourage him to eat.
When you get in from a walk, play with him for a bit. maybe some discipline as well. Have him sit or something. Stay and then throw his toy, as he holds his sit. Then tell him go get it. Reward with praise (or a kibble).
Once you play with him for a bit, tell him, lets get dinner time..

Do Not Let him snack in between or during prep. IE: Don't give him a peice of your chicken or anything else.
Prepare his food as he is with you in the kitchen, holding a sit or lay down.
Mix up his food and put it down. Do not stand over him watching. Carry on with what ever in the kitchen so you are near but see him out of the corner of your eye. If he walks away disinterested, call him back. Pick up a piece of food and say here boy.
Once he comes back, put it down in front of him. Hopefully he will take interest. If so, get up and carry on, near by so he can see you.
If he still doesn't eat, pick up his dish.
If you haven't added yogurt, try putting a bit of warm water on the kibble. Once soaked in, try again.

Maximo makes good points although in my opinion even an older dog is prone to hypoglycemic episodes if there blood sugar drops too low, (usually not enough food) as well as diabetes if there sugar levels go too high (too much of the wrong foods IE: Sugar and Sugar substitutes).
It is a careful balance so is why diet is so important for all dogs but especially the little ones.
Good Luck!