Heat oil in a large saucepan over medium heat. Saute onion, bell pepper and garlic. When onion is translucent add salt and tomato paste. Reduce heat to low and cook 2 minutes. Stir in the beans and rice.
Pour the liquid from the beans into a large measuring cup and add enough water to reach a volume of 2 1/2 cups; pour into beans. Cover and cook on low for 45 to 50 minutes, or until liquid is absorbed and rice is cooked.