Salvatore is the best safecracker in Lost Heaven, and reputed for unlocking every safe in America. He assists Tommy Angelo in the mission Visiting Rich People by opening the safe in the Prosecutor's office. He mentions that he had inherited expertise in safe cracking from his grandfather.
In Mafia II, a man named Salvatore helps undercover FBI agent Frankie Potts break into Alberto Clemente's safe. Given Salvatore's expertise in lock picking and safe cracking, it may be safe to assume they are the same person.
In the mission Visiting Rich People, Salvatore can optionally teach you how to unlock the Prosecutor's Silver Fletcher.