Place the chicken breasts in a baking dish or casserole pan along with the onion and pepper, if desired.
In a Cuisinart or blender, combine the orange juice, lime zest, lime juice, garlic cloves, cumin, and oregano. Blend for about 30 seconds; if there’s a “pulse” option, use that so you don’t turn the marinade into soup.
Then, drizzle in the olive oil while the blender is in action.
Pour ½ cup of the marinade into a bowl for the salsa. Pour the remainder over the chicken, cover, and place in the refrigerator for at least 3 hours to marinate.
Add the chopped avocado, tomatoes and pineapple to the ½ cup of reserved marinade. Mix together with salt and pepper to taste,cover, and refrigerate.
About an hour before you want to serve, preheat oven to 350°F with the rack centered.
When oven is ready, place the chicken uncovered in the center of the oven and set the timer for 45 minutes.
Remove the salsa from the refrigerator.
Saute the chopped onion and minced garlic in olive oil. Once the aromas are released (a minute or two) add the beans. If canned, add with the juices. If prepared from dried, add a little chicken broth or water to soften the dish a little bit.
Cook or steam the rice in 2 cups water.
When the chicken reaches an internal temperature of 160-170°F (about 45 minutes), remove from oven. Place the chicken on a cutting board, reserving the marinade.
Slice the chicken and serve over the rice and beans. Drizzle the marinade from thebaking pan over the dish. Top with a generous scoop of salsa.