Heat grill to high. Place water, salt, and whole garlic cloves in a small saucepan and bring to a boil on the grates of the grill. Remove from the heat and let cool slightly.
Brush steaks on both sides with the garlic-water mixture and season with pepper. Grill for 4 to 5 minutes per side for medium-rare doneness, basting with the garlic-water mixture every minute or so.
While the steaks are grilling, mix together the oil, finely chopped garlic, and parsley in a medium bowl and season with salt and pepper, to taste. As soon as the steaks come off the grill, pour the sauce over the steaks and let sit 5 minutes. Cut the steak into 1/4-inch thick slices and serve.