Make the marinade by combining the soy sauce, peach juice, oil, dried onion flakes, garlic and fresh ground black pepper. Whisk well to combine.
Cut the steak into 1 inch pieces and add it to a gallon size resealable bag. Pour the marinade over the steak, seal the bag tight and refrigerate for 1 to 6 hours.
If using wooden skewers, soak them in water for 30 minutes. Thread the steak and chopped vegetables alternately onto the wooden skewers, keeping a little space between each piece.
Heat gas grill to medium-high and grease lightly with oil. Grill the kebabs for just a few minutes on each side (8-10 minutes maximum), according to how well done you like your steak. Allow the kebabs to rest for 5 minutes before serving.
Make Ahead Instructions: The steak can marinate for up to 6 hours. The vegetables can be chopped ahead of time so all you have to do is assemble and grill!Variations:
Vegetables: Use any veggies you like, and cut them big so they hold their own while the steak cooks.! I always include bell peppers and onions on my kabobs but you could also add mushrooms, zucchini, summer squash, or your favorite type of vegetable for grilling.
Cook in Oven: I think the flavor of steak kabobs is best when cooked on a gas grill, but to cook in the oven, turn oven to broil on high. Place kabobs on the top oven rack and cook for -15 minutes (depending on how well done you like your steak), rotating during cooking.
Cook in Grill Pan or Skillet: Heat on stove over medium-high heat. Cook kabobs for several minutes, rotating once or twice, until cooked through.