In large saucepan, combine beans, oil, salt and 6 cups (1.5 L) water. Bring to a boil and then reduce heat to simmer. Cover and simmer about 1 hr. 10 min., stirring occasionally, until water is mostly absorbed and beans are moist and tender.
Stir peppers, onion, rice, cumin and oregano into saucepan mixture. Add 2 cups (500 mL) water; bring to a boil. Reduce heat to low. Simmer, covered, 15 to 20 min., until rice is tender and liquid has been absorbed.
Fluff beans and rice mixture. Garnish with cilantro, if using, to serve.
To substitute brown rice instead of white rice, in step 2, add 2 1/2 cups (625 mL) water to the saucepan (instead of 2 cups/500 mL). After brown rice is added, cook about 40 min., until the rice is tender.