Our 2 & 1/2 year old recently adopted small dog licks us excessively, why does

[Pam]

he do this and is this normal? He was neutered at the SPCA the day before we adopted him and we provide him with good dry dog food twice a day as well as a full bowl of water. He has had all his shots. He licks any part of our exposed body so much ( 5 mins or more if we let him) that we have to tell him to stop or gently push his face away. We don't know his background or history. He weighs 15.3lbs and is part Lhasa Apso and Schnau-Tzu. We love him very much but the licking drives us crazy. He is a very good dog, he hardly ever barks but does have some separation anxiety when we leave and seems nervous and jumpy by strange noises. He acts more like a puppy sometimes. We would take him for frequent walks but he won't go to the bathroom outside just inside on the floor so we had to gently house-train him but he caught on only after 2 weeks. We don't know how to stop his excessive licking or why he might be doing this behavior?