Salinas knocked in a loose rebound in the 92nd minute and Gordon scored on a header a minute later to give San Jose (5-7-6) a second comeback victory in two seasons against the Galaxy at Stanford. The Earthquakes came from two goals down to beat LA 4-3 last June 30.
Marcelo Sarvas scored in the 20th minute and Hector Jimenez in the 65th for Los Angeles (7-7-3).
Gordon scored his first goal of the season in the 68th minute to pull San Jose to 2-1. The Earthquakes' chances looked dire after defender Victor Bernardez saw two yellow cards in the space of eight minutes and was sent off in the 77th minute, leaving San Jose down to 10 players.
Gordon got the game-winner moments later off a chipped cross from just inside Los Angeles' penalty area by San Jose midfielder Sam Cronin.
Landon Donovan and Robbie Keane assisted on both goals for the Galaxy, but L.A. was left to deal with failed opportunities after Bernardez's ejection, especially an 88th-minute save by Busch on Jimenez.
A prone Cudicini blocked a 50th-minute rebound shot from 8 yards by San Jose midfielder Marvin Chavez. The veteran keeper, who joined LA this year, was unable to come up with the critical saves in the dying minutes, however.