Remove the duck from the package and pat dry with paper towels. Remove the innards and set aside (save these for making duck broth). Place in a large roasting pan.
In a small bowl, combine the salt, garlic, five spice, and Szechuan peppercorn and mix together. Rub the mixture on all sides of the duck.
Place the quartered orange pieces inside the cavity of the duck. Place in the fridge, uncovered, overnight.
Remove the duck from the fridge and let it come to room temperature for about 30 minutes. Preheat the oven to 425 degrees.
Place the duck on on a roasting rack, breast side up, in the roasting pan, This helps to keep the skin crispy on all sides. Place the roasting pan on the middle rack in the oven.
Cover with foil and roast for 40 minutes. Remove and baste with the rendered fat in the bottom of the pan. Be careful as it will be hot.
Place back in the oven and roast another 30 minutes. Remove the foil for the last 20 minutes.
Remove the duck from the oven and spoon out all the duck fat (see note 6). Brush the duck with the glaze.
Place back in the oven for 10 minutes. Remove and brush with glaze again. Place back in the oven for another 10 minutes. Remove from oven and let the duck rest for 10-15 minutes.
Carve and serve plain or drizzled with remaining orange sauce.