Bacon, chopped onions, ketchup, and molasses provide a rich sauce for these "baked" beans, which are prepared entirely in the microwave. They're the perfect accompaniment to hot dogs or hamburgers.
In a shallow 2-quart microwave-safe dish with a lid, stir together bacon and onion. Microwave on high, uncovered, until onion is tender and bacon has rendered some fat, 5 to 7 minutes. Stir in beans, ketchup, molasses, mustard powder, and 1/3 cup water. Cover and microwave until beans are tender and liquid has thickened, 10 to 12 minutes. Stir in vinegar, and serve alongside hot dogs or burgers.