Make the brine. Mix your hot water with the sugar, salt, and fish sauce and stir until the sugar is combined. Add the 3 cups of cold water, ginger slices, and smashed garlic and stir well. Pour the liquid into a large ziplock bag or dish and submerge the pork chops in the liquid. The key is to make sure they're totally covered with the brining solution! Transfer them to the fridge for at least 4 hours, up to 24 hours.
Make the hoisin glaze. In a small saucepan, combine the hoisin, soy sauce, rice vinegar, honey, ginger, garlic, and sriracha and stir well. Bring to a gentle simmer over medium heat for 5 minutes. Remove the glaze from the heat and let it cool to room temperature.
Preheat your grill. Before using your grill, make sure to clean the grates of any food and debris. Lightly grease the grates with nonstick spray. Preheat your grill to medium heat. If you’re using charcoal, move all the hot coals to one side. Close the lid and wait at least 15 minutes, until the temperature reaches 450 F.
Prep the pork. Remove the pork from the brine and lay them on a paper towel lined tray. Discard the brine. Pat the pork chops as dry as possible and season the outside lightly with salt and pepper.
Grill and glaze the pork. Lay the pork chops on the grill and grill for 2-3 minutes on the first side, just until grill marks appear. Flip the pork chops and use a basting brush to generously spread some of the glaze on the grilled side. Cook for another 2 minutes, then flip and glaze again. Continue to flip the pork every 2 minutes, glazing as you go, until the pork is cooked to at least 150 F, and well coated in the glaze. Remove the pork from the grill and let it rest before slicing and serving.