In a large skillet, cook bacon and onion over medium heat until bacon is crisp and onion is tender.
Cut green beans into 1-inch pieces, then put in large saucepan and cover with water. Bring to a boil.
Cook, uncovered, for 8–10 minutes or until crisp-tender. Drain well. Add to bacon mixture. Sprinkle with salt and pepper; toss to coat.