For sauce, in a small saucepan cook onion, garlic, and chili powder in margarine till tender. Stir in tomato sauce, vinegar, honey, salt, and pepper. Bring to boiling, stirring constantly. Boil 5 minutes or till slightly thickened. Meanwhile, trim fat from flank steak. Score steak diagonally into diamonds on both sides. Brush with sauce. Grill steak on uncovered grill directly over medium coals for 7 minutes. Turn and grill to desired doneness, allowing 5-7 minutes more for medium. Brush occasionally with the remaining sauce. To serve, thinly slice the flank steak across the grain. Broiling Directions: Place meat on the unheated rack of a broilerpan. Broil 8 cm from heat for 6 minutes. Turn and broil to desired doneness, allowing 6-8 minutes more for medium. Brush occasionally with sauce. Per serving: 240 calories, 21 g protein, 5 g carbohydrates, 14 g fat, 58 mg cholesterol, 304 mg sodium, 436 mg potassium.