In a Dutch oven over medium heat, cook beef and onion, crumbling meat, until beef is no longer pink and onion is tender, 6-8 minutes., Add next 5 ingredients; cook 1 minute longer. Stir in water, both types of beans, diced tomatoes and tomato sauce. Bring to a boil; reduce heat. Stir in squash; simmer, covered, until squash is tender, 20-25 minutes. Stir in vinegar. , If desired, serve with chopped avocado, Greek yogurt and shredded mozzarella cheese.