Rub salt and pepper evenly over roast; let stand at room temperature 15 minutes.
Brown roast in an ovenproof Dutch oven coated with cooking spray over medium heat until browned on all sides. Remove roast, and set aside.
Add onion to Dutch oven, and sauté 3 to 5 minutes.
Return roast to Dutch oven. Stir together tomatoes, ketchup, vinegar, and brown sugar. Pour tomato mixture over roast.
Bake, covered, at 350° for 1 hour. Stir in beans, and bake, covered, 45 more minutes. Stir beans and sauce; bake, uncovered, 15 more minutes or until meat thermometer inserted into thickest portion of roast registers 160°. Remove from oven, and let stand 5 to 10 minutes before slicing. Slice roast evenly into 8 chops, and serve with beans and sauce.