Sort and wash beans; place in a large Dutch oven. Cover with water to 2 inches above beans; cover and let stand 8 hours. Drain beans.
Heat oil in pan over medium-high heat. Add onion and garlic to pan; sauté for 4 minutes. Stir in beans, 10 cups water, and the next 4 ingredients (through sausage); bring to a boil. Reduce heat, and simmer 1 1/2 hours or until bean mixture thickens. Serve over rice. Garnish with green onions, if desired.