Cook rice according to package directions. Meanwhile, in a large saucepan, saute green peppers, onions and garlic in oil until tender. Add the Cajun seasoning, salt and pepper. Cook and stir for 3 minutes.
Stir in the beans, tomatoes and water. Bring to a boil. Reduce heat; cover and simmer for 10 minutes. Uncover; cook for 5 minutes. Serve over rice.