Mouth is what a dog has for expressing all his emotions. A dog may lick your face to express love. Therefore, being licked by a dog or a probable rabid animal is not dangerous unless the lick is across raw, broken skin.
Rabies- hyped fear
Please be assured dogs are not snakes. You cannot get rabies if a dog licks you. The fear of rabies is much hyped and away from reality. Rabies eradication program involves funding of many international NGOs. That's millions of dollar.
Dog are living with the human for many thousands of years. Dogs do not possess any venom that can kill any human just by licking.
Rabies virus is neurogenic, that means to transmit rabies virus from infected dog to human, exposure to the nerve is necessary. Rabies virus cannot be transmitted through blood (like AIDS or malaria).
Therefore, it is very safe to let your dog or any dog lick you if he likes you. 
A word of caution though for the personnel working in a laboratory. Rabies virus can pass through cornea during handling, therefore be extra cautious in a laboratory. This virus is a different one, we veterinarian call this virus fixed virus and those found in dogs natural environment is called the street virus.
One fact worthwhile to mention here, Now there is growing fashion to give mouth to mouth kiss to a dog. This is dangerous. Pet owners who kiss their dog on mouth or lips may get rabies. Therefore, Giving your pooch a smooch may not be a good idea.
