Preheat oven to 350 degrees. Grease a mini muffin tin.
Place ground Italian sausage in a large, deep skillet. Cook over medium high heat until evenly brown. Drain and remove from heat.
Stir Monterey Jack cheese and Colby cheese into the warm sausage to melt. Stir in salsa.
Gently press wonton wrappers into the prepared mini muffin pan so that the edges are extending. Place a heaping tablespoon of the sausage mixture into each wonton wrapper. Bake 10 minutes in the preheated oven, or until wonton edges begin to brown.
Transfer baked filled wontons to a serving platter. Dollop each with approximately 1 tablespoon sour cream. Sprinkle with scallions.