Place bacon in covered casserole dish. Microwave on HIGH for 4 minutes. Combine salt and flour. Dredge liver in flour; set aside. Drain all but 2 tablespoons fat from casserole dish. Place liver in dish; cover with excess flour. Add onions on top. Microwave on HIGH for 5 minutes. Reduce power to 50%, turn over and rearrange liver. Microwave 11-15 minutes or until liver is tender.