Findley scored the game-winner three minutes from the end with his team-leading fifth goal of the season.
With the win, RSL takes a four point lead over the Los Angeles Galaxy atop the Western Conference table. Toronto FC is in a four-way tie at the bottom of the Eastern Conference with just 22 points thanks to a 1-7-0 road record.
Salt Lake's Jamison Olave got the game's first goal in the 63rd minute. Toronto tied the score six minutes from the end with Amado Guevara's third goal of the season.