A kong is a movement in Parkour, the art of movement, in which one runs towards an object, dives, and uses his arms to push himself past. To say "Let's kong this bitch" is like saying "let's blow this joint."
Guy: Man, this is lame.
Guy 2: Yeah man, let's kong this bitch.
Person two: (oh god it's going to be good)
Person one:"...decided she was going to attack me from behind and come at me with a 2 by 4. So I flipped her over onto the ground and showed her what I'm made of."