With Ru Paul's drag race, yes technically, you can just start on any season since they really don't have anything to do with each other.
Season 1 and 2 are very dated at this point but still good seasons, and the show really kicked into high gear on season 3 through 6, with seasons 4 / 5 / 6 being the best.
My advice, watch season 6 first. After watching each episode go find and watch the after show which is called, Untucked. Each episode of Untucked goes hand-in-hand with each episode of Rupaul's drag race and gives a hell of a back Room story to each episode. It's a must watch with each episode to fully experience each episode, especially on season 6.