Cut bacon into one-inch segments and place the bacon and chopped onion in a skillet. Cook over medium heat until browned, stirring often. Remove to a plate.
Add beans to bacon grease and continue cooking over medium heat until they are to desired tenderness. Add vinegar and sugar and stir. Add bacon and onions back and let simmer for a few minutes, stirring often. Salt and pepper to taste.
Serve warm.
