Being salty has various meanings from being rude to crass to other insulting and uncomplimentary adjectives. That isn’t what I have always thought that particular adjective was defined.
“Salty” which derives from the Middle English “Salti,” is more of a naval term. Navy men reference a sailor’s “being salty” to being experienced. I suppose it would refer to being constantly “at sea” upon the ocean’s “salty waves” the perpetual kiss from which would render one’s skin somewhat “salty.”