The most important thing is you taught her the "No lick" command. And you said yourself she usually responds well to that command and stops licking, right? So, just continue to reinforce that command. Some dogs are more licker-friendly than others, and they just love to get up close, personal and take a lick.
She does this only with people's faces, etc or does she have licking problems in general?
Generally, it's hands, legs, whatever.....but people will stick their face in hers and of course she's going to lick them! Thing is, when we go to the doggie park, she could not be less bothered with the other dogs....she's there to visit the people, get the free butt rub, and then lick them!