Salvador is a Pokémon Trainer from Cherrygrove City who showed up as a one-off opponent in the Silver Conference arc.
He's best known for being Ash's first matchup during the Screening Round in A Claim to Flame!. The computer paired them up, and Salvador opened with his Furret against Ash's Pikachu. It was a solid battle—Furret gave Pikachu a real fight—but Ash came out on top and moved forward in the tournament. What happened to Salvador after that is anyone's guess; the show never followed up on whether he won his remaining two Screening Round matches or made it any further.
Content compiled by AnimeList.moe from publicly available sources.