Heat oil in a large nonstick skillet over medium-high heat. Add onion, bell pepper, and garlic; sauté 2 minutes. Add chopped tomato, capers, cumin, and crushed red pepper; cook over medium heat 5 minutes, stirring occasionally. Add fillets to skillet, spooning sauce over fillets. Cover and cook 10 minutes or until fish flakes easily when tested with a fork.