Heat olive oil in a large skillet over medium heat.
Add chopped onion and sauté until soft and translucent.
Stir in minced garlic and cook until fragrant.
Add diced bell pepper and cook for 2–3 minutes.
Stir in black beans, corn, and taco seasoning.
Add tomato sauce and mix until well combined.
Simmer the mixture for 5 minutes on low heat.
Add cooked rice and gently fold into the mixture.
Season with salt and black pepper to taste.
Remove from heat and let rest for 5 minutes.
Garnish with fresh cilantro and serve warm.