Place bell pepper in a 9-inch pie plate, cover w/ plastic wrap & vent, microwave @ high 2 minutes, remove & set aside. Wipe pie plate. Quarter fish, arrange in pie plate, sprinkle with pepper; top with bell pepper and onion. Microwave, uncovered, @ high 7-8 minutes until fish flakes easily. Drain & cover. Combine salad dressing and next three ingredients in 1-cup glass measure; stir. Microwave @ high for 1 minute. Serve sauce with fish and garnish with lemon wedges.