Pre cook your rice as you normally would or per the instructions switching 1 cup of water for one cup of chicken stock or ham stock. In a skillet heat your oil over medium heat. Add the red onion, red and green peppers and sauté for a few minutes add the garlic and sauté for about 1 more minute. Reduce heat to low add the beans, rice, vinegar cayenne, pimentos, and mango cook for an additional 3 - 4 minutes.