In small non-stick skillet, sprayed with vegetable cooking spray, over medium heat, saute onions 2 to 3 minutes or until lightly browned. Add garlic and stir 30 seconds. Allow to cool for about 4-5 minutes.
In food processor fitted with metal blade, puree onion mixture, peppers and salt. With motor running, slowly add poaching liquid to red pepper mixture until sauce is smooth.
Pour sauce into 2-cup glass measure and heat in microwave at HIGH (100% power) 30 seconds or until hot.