For the tilapia marinade, combine lime juice, 1 TBS olive oil, 2 TBS cilantro, 1 tsp garlic, 1/2 tsp salt, and sugar in a shallow dish. Add tilapia and marinate 15 minutes, turning once.
To prepare the bean and rice mixture, cook the rice according to package directions and keep warm while the tilapia is marinating. Preheat oven to 400 degrees. In a large, high-sided skillet or saucepan, heat 2 TBS olive oil on medium heat. Add remaining garlic and onions; sauté until translucent, about 5 minutes, stirring. Add 2 TBS cilantro, oranges, tomatoes, beans, oregano, 1 tsp salt, pepper, and cayenne. Cook, uncovered, until hot, 7 to 8 minutes, stirring occasionally.
Transfer hot rice to a 9 by 13 inch or 2-1/2 to 3 quart baking dish. Spoon the bean mixture on top of rice and gently blend. Slightly overlap tilapia fillets on top and scrape marinade over fillets. Bake until the flesh of the tilapia just begins to flake at the nudge of a fork, 16 to 20 minutes.
Tips: A chopstick works well when you need to stir tender mixtures of rice or couscous to prevent the grains from breaking up.
Use leftover cooked rice (2 cups), if desired, and reheat in the microwave for 2 to 3 minutes.
