In a large skillet, heat 3 tablespoons of olive oil over medium-high heat. Add the onion and peppers. Generously sprinkle with salt and pepper and sauté until tender, about 6-8 minutes. Let cool.
Combine the sautéed veggies with rice and beans. Taste and adjust the seasoning. If the mixture tastes dry, stir in 1-2 tablespoons of olive oil, as needed.