We may taste nice and certainly people who have just been exercising often find that it is much worse with their dog licking them loads and with more frequent long licks. Certainly your skin may be more salty and they may like the taste. However, the most likely explanation is actually quite a simple one. It is OUR reaction to them licking that means they do it again. We probably laugh, at the very least engage in getting them to stop it. It is these human behaviours that offer a rewarding experience for your dog and 'what gets rewarded gets repeated'. And so you then have built a chain of behaviours,that you arrive home, dog licks you furiously, you laugh or try to get them to stop and suddenly that is your dog's new greeting routine!
Science has provided evidence to support that puppies licking their mothers mouth is seen as a pacifying action. But this is usually confined within the litter. So how do we stop this behaviour in our home. It is actually quite simple and quick to resolve. As soon as your dog licks the greeting ends by you standing up and leaving the room for 30 secs. This is a direct consequence that your dog will link with his licking. The purpose of his licking is to greet you, so when you leave that is the very least desired result for your dog.
However, I much prefer the approach of giving your dog something else to do instead by offering a toy. If you know when it happens be prepared when you arrive home and give a favourite toy positioned at the door ready, Then have a really good tug game for 2 mins. He can then continue to carry the toy in his mouth afterwards too! You can build up some lovely new learning that when he tries to lick you you pull out the toy for him to carry in his mouth. Building up alternative behaviours to those behaviours we don't want is the best training approach for many of the behaviours our dogs do we don't like.