In a skillet, cook garlic and scallions in olive oil for about 3 minutes. Pour in whiskey, increase heat to high and bring to a boil. Remove from heat. Stir in Dijon mustard, Worcestershire sauce, and sugar.
Season steaks with salt and pepper if desired. Brush both sides of steaks with whiskey mixture and put on a hot grill or broiler. For medium rare, cook until internal temperature is 145°. Baste meat occasionally, and turn once.
In a bowl, combine any remaining whiskey mixture, the green peppers and either grill for 4 minutes or place in microwave for three minutes. Add the tomatoes to the green pepper mixture for the last minute of microwaving or grilling.