Rinse beans well. Cover beans with about 9 cups of water, and soak beans for several hours or overnight.
In a large sauce pot, sauté onion, green pepper, and garlic in olive oil until tender. Add salt, pepper, oregano, cumin, bay leaf, vinegar, and dried beans to saucepot. Cover with about 8 cups of water. Bring to a boil and let cook for about one minute. Reduce heat to medium-low and cook for about 1 to 2 hours, or until beans are tender. If beans become dry, add another cup of water. Adjust salt as needed. Remove bay leaf. Serve beans over steamed rice.
When soaking or cooking beans, use about 3 cups of water for each cup of dried beans.