Fry bacon until done but not crisp. Remove bacon, then lightly fry diced onions in bacon grease. Drain bacon grease. Blend bacon and onions with Miracle Whip, salt & pepper, sugar & vinegar. This mixture can be prepared ahead and refrigerated until about read to eat.
Just before you are ready to eat, heat green beans in microwave until piping hot. Drain off liquid. Add Miracle Whip mixture. Reheat in microwave. Do not overheat as the Miracle Whip will separate.