In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until translucent, about 3-4 minutes.
Add the ground beef to the skillet, breaking it apart with a spatula. Cook until browned, about 5-7 minutes. Drain excess fat if necessary.
Stir in the sliced red and yellow bell peppers and minced garlic. Cook for another 3-4 minutes until the peppers are tender.
Season the mixture with cumin, smoked paprika, salt, and black pepper. Stir well to combine and cook for an additional 2 minutes.
Add the cooked rice and soy sauce to the skillet. Mix everything together and heat through for about 2-3 minutes.
Serve the beef and pepper mixture in bowls, garnished with sliced green onions and sesame seeds if desired.