Remove giblets and excess fat from the duck cavity. Pat the duck very dry with paper towels. Prick the skin all over with a skewer, taking care not to pierce the meat. Rub the salt and optional five-spice over the skin and inside the cavity.

Set the duck breast-side up on a wire rack over a rimmed tray. Refrigerate uncovered for 8 to 12 hours so the skin dries. Keep it on the bottom shelf and away from ready-to-eat foods.

Whisk the honey, rice vinegar, and hot water. Let the duck sit at room temperature for about 30 minutes while the oven heats to 425°F. Brush a thin layer of glaze over the skin.

Roast the duck breast-side up on the rack for 15 minutes. Reduce the oven to 350°F and continue roasting, rotating the pan once, until a food thermometer reads 165°F in the thickest breast and innermost thigh. A 4 to 5 pound duck may take about 2 1/2 to 3 hours total; oven and bird size affect the timing.

Rest the duck for 20 minutes before carving. Pour off the rendered fat carefully and save it for another use if desired. Slice the skin and meat thinly.

Warm the pancakes according to the package directions. Serve duck with cucumber, scallions, hoisin, and pancakes so everyone can assemble a small roll.