My older yorkie and my maltese has been licking their paws a lot. I was told it might be a nervous behavior also. I try to distract them by giving them chew toys or bitter apple and just saying NO.
It is also funny as it is also a sign that my Yoshi is falling asleep when he starts chewing or licking his paws. All of a sudden he will fall asleep with his face either on the toy he is chewing/licking or his own paws. Too Cute.