In a medium bowl, whisk together the steak sauce, Worcestershire sauce, garlic, onion powder, & black pepper. Set aside.
Mix the potato chunks with the water in a medium sized dish, cover with vented plastic wrap, and cook for 6 minutes in the microwave. Drain the water, & set the potatoes to the side to cool enough to handle. OR - use a baked potato.
Thread the skewer through the kabob components as so: First a steak cube, then an onion layer, a potato, another onion layer, & finishing off with another steak cube. Do this until all the steak & potatoes have been used.
Brush the entire kabob with the sauce mixture. Grill on med-high heat for 5 minutes. Turn; and cook for an additional 3-5 minutes – basting with the remaining sauce.