1. Sort and wash beans; place in a large saucepan. Cover with water to 2 inches above beans; cover and let stand 8 hours. Drain beans.
2. Return beans to saucepan. Cover with water to 2 inches above beans; bring to a boil. Cook 10 minutes; drain.
3. Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add sausage; cook 6 minutes or until browned. Add onion and next 5 ingredients (through garlic); cook 8 minutes. Stir in beer; bring to a boil. Cook 2 minutes, scraping pan to loosen browned bits. Place sausage mixture in a 6-quart electric slow cooker. Add beans, stock, red pepper, black pepper, and bay leaves. Cover and cook on LOW for 8 hours.
4. Discard bay leaves. Stir in 1/4 cup green onions and vinegar. Serve over rice; sprinkle with remaining 1/4 cup green onions.