I normally use fat wild duck breasts from mallards and pintail, or specklebelly goose breasts here. But Pekin or Moulard duck breasts would be more traditional. Once made, these smoked duck breasts will keep in the fridge a week, and they freeze well.
Remove the duck breasts from the refrigerator. To make the dry rub, combine the kosher salt, Sichuan peppercorns, black peppercorns, and curing salt in a spice grinder and grind to a powder, or grind together in a mortar with a pestle. Moisten the duck breasts evenly with the wine, then coat with the spice mixture. Wrap each breast individually in plastic wrap, place in the refrigerator, and let cure for at least 4 hours or preferably 12 hours. If using large breasts, leave them to cure for 24 hours (see headnote).
Once the breasts have cured sufficiently, rinse off the cure and pat them dry. Set them, skin side up, on a cooling rack and let dry for 2 to 3 hours. If you can, direct a fan on the duck so it dries thoroughly.
Line a wok with aluminum foil so that about 2 inches of foil extend beyond the rim around the perimeter. You will use this to seal the wok. Put all of the smoking ingredients in the bottom of the wok, followed by a rack (or use 4 cheap chopsticks or wooden skewers to improvise a rack). Place the duck, skin side down, on the rack. Seal the wok and set it on the stove top. If you are just using foil, drape it over the top of the wok and crimp the edges. If you have the lid, put the lid down and use the excess foil lining the wok to seal everything. Be sure to have your stove exhaust fan on high. (If your exhaust fan is not very powerful, you might want to consider doing this outside on the grill.)
Turn on the heat to high for 3 to 5 minutes, until the smoking ingredients just begin to start smoking. You will hear lots of snapping, crackling, and popping. Turn the heat to medium and smoke the duck for 20 to 30 minutes: Normal-size duck breasts will need 20 minutes; really large ones such as Moulard or goose breasts will need the full 30 minutes.
Remove the lid and take the duck breasts out. You can let them cool and store them in the fridge for a day or two at this point. To finish them, in a sauté pan, heat the 2 teaspoons [[the amount you call out isn’t possible because in ingred list you have 2 teaspoons]] of the vegetable oil over medium-high heat. Add the breasts, skin side down, and cook until the skin is crisp. Do not cook the meat side, which will be cooked already. Remove the breasts from the pan, slice them, and set them aside while you cook the vegetables.
To cook the vegetables, turn the heat to high under the same pan you used to crisp the skin of the duck. Add the mushrooms and toss to coat with the oil remaining in the pan. Let the mushrooms sit undisturbed for 2 to 4 minutes, until they begin to release their water. Add the teaspoon[[see query above re amount in ingred list]] sesame oil, the bok choy, and the ginger and stir-fry for 1 minute.
Add the sugar, soy sauce, and stock and toss to combine. Boil this furiously for 4 minutes, letting the liquid cook down and thicken. Turn off the heat, add the sliced duck and the chiles to taste, and toss to combine. Serve at once.
Notes
Note that the prep time does not include curing time.