**Prepare the Chicken:** In a large bowl, season the chicken pieces with salt, pepper, oregano, cumin, and a splash of vinegar. Set aside to marinate for at least 15 minutes.
**Sauté Aromatics:** Heat 1 tablespoon of olive oil in a large pot or Dutch oven over medium-high heat. Add the chopped onion and green bell pepper and sauté until softened, about 5 minutes. Add the minced garlic and cook for another minute until fragrant.
**Sear and Simmer:** Add the marinated chicken to the pot and sear for a few minutes until lightly browned on all sides. Stir in the tomato sauce and cook for 2 minutes. Pour in the remaining vinegar and chicken broth. Bring to a simmer, then reduce heat to low, cover, and cook for 20-25 minutes, or until the chicken is cooked through and tender. Adjust seasoning if needed.
**Cook the Beans:** While the chicken simmers, heat 1 tablespoon of olive oil in a separate saucepan over medium heat. Add the chopped onion and sauté until softened. Add the minced garlic and cook for 30 seconds. Stir in the drained beans, water (or broth), salt, and cumin. Bring to a simmer, then cover and cook for 10-15 minutes, allowing the flavors to meld.
**Cook the Rice:** In a medium pot or rice cooker, combine the rice, water, and salt. Bring to a boil, then reduce heat to low, cover tightly, and simmer for 15-20 minutes, or until the water is absorbed and the rice is tender. Fluff with a fork.
**Assemble the Plate:** To serve, place a generous portion of white rice on one side of the plate. Spoon the stewed chicken next to the rice, followed by the stewed beans. Garnish with sliced avocado or fried plantains if desired.