Wash the lettuce, shake as much water off as possible and tear into pieces, or shred coarsely and place in salad bowl. Place bacon on a microwave roasting rack set in a baking dish. Cover with a paper towel. Microwave at high (100%) 4 minutes. Drain on a paper towel. Remove roasting rack from baking dish. Stir in onions. Microwave at high (100%) until onions become transparent, 1 to 2 minutes. Stir in vinegar, water, sugar, salt and pepper, mixing well. Microwave at high (100%) 30 seconds. Pour hot mixture over lettuce, coating all the greens. Crumble bacon and toss lightly until lettuce is wilted. Serve immediately. Makes 4 servings.