In a large pot, bring water to a rolling boil and add kosher salt. Carefully add the potato wedges and cook for about 10 minutes until tender yet firm. Drain and cool slightly.

In a mixing bowl, combine garlic powder, onion powder, lemon zest, lemon juice, olive oil, and black pepper. Whisk until blended to create a marinade.

Add cooled potato wedges to the marinade and gently toss until coated. Let sit for about 15 minutes while the grill heats.

Preheat the grill to medium-high (about 400°F). Grill potato wedges for approximately 20 minutes, flipping every 5 minutes until golden-brown and crispy.

Transfer grilled potatoes to a bowl, toss with reserved marinade and fresh parsley. Serve immediately.