Remove stems and seeds from red peppers.
Using coarse blade of food chopper, grind peppers and onions, reserving juices.
In Dutch oven or large saucepan combine peppers and onions and reserved juices.
Stir in sugar, vinegar, and salt.
Bring to boiling; boil gently, uncovered, for 20 to 25 minutes.
Cool; cover and chill till needed.