In a large bowl, mix together crabmeat, cream cheese, onions and mayonnaise with a spoon.
Spray 12 muffin cups with cooking spray. Gently place 1 won ton wrapper in each cup, allowing edges of wrappers to extend above sides of cups. Fill evenly with crabmeat mixture.
Bake 18 to 20 min. or until edges are golden brown and filling is heated through. Serve warm. Garnish with chopped green onions, if desired.
Note: For a crispier Rangoon, bake won ton wrappers in muffin cups at 350 degrees for 5 to 7 min. or until lightly browned. Fill evenly with crabmeat mixture and bake 6 to 8 min. or until filling is heated through.