Preheat oven to 400°F. Mix first 4 ingredients in medium bowl until well blended.
Place 3 tortillas on baking sheet. Spread with shrimp mixture, then top with second tortilla. Sprinkle tops with additional cheese and green onions, if desired.
Bake 5 minutes or until cheese melts. Cut each quesadilla into 8 wedges. Serve warm.