Spray medium nonstick sauté or omelet pan with cooking spray; heat over medium heat. Add bell peppers; cook 3 to 4 minutes or until tender. Add ham and onion; cook 2 to 3 minutes more or until onion is tender. Remove from skillet; set aside and keep warm.
Add 1/2 carton (about 1 cup) Egg Beaters to skillet; cook 3 minutes or until edges start to set. Using a rubber spatula, gently lift edges while tilting pan to allow uncooked Egg Beaters to run beneath. Cook until set.
Place half of vegetable mixture and 1/4 cup cheese over half of cooked Egg Beaters. Fold in half over filling. Slide omelet onto serving plate; keep warm. Repeat with remaining ingredients.