Preheat oven to 350°F. Mix cream cheese, mayo, crabmeat and onions. Spray 12 (2-1/2-inch) muffin cups with cooking spray. Place 1 won ton wrapper in each cup, allowing edges of wrapper to extend above side of cup. Fill evenly with crabmeat mixture. Bake 18 to 20 min. or until edges are golden brown and filling is heated through. Serve warm.