COOK bacon in large skillet until crisp. Remove bacon from skillet; drain on paper towels. Discard drippings from skillet. (Do not wash skillet.)
PLACE asparagus in microwaveable casserole or 10x4-inch dish. Add water. Microwave on HIGH 4 to 5 min. or until asparagus is crisp-tender. Meanwhile, add onions to skillet; cook and stir 5 min. or until tender. Stir in dressing.
DRAIN asparagus; top with sauce and crumbled bacon.