Rinse swordfish with cold water; pat dry. Sprinkle with pepper. Coat a skillet with cooking spray. Add butter and place over medium heat until butter melts. Add fish to skillet and cook until browned on both sides. Place in a 10 x 6 x 2 inch baking dish.
Wipe skillet with a paper towel and coat with cooking spray. Place over medium heat until hot. Add onion and garlic; saute until tender. Add tomato, chiles, wine, vinegar, and salt. Bring to a boil. Remove from heat and spoon mixture over steaks. Bake, uncovered, at 450 degrees for 10 minutes or until steaks flake easily when tested with a fork. Remove steaks from dish to a warm platter, using a slotted spoon. Yield: 4 servings (169 calories per serving).