Prick duck all over with a small knife or fork. Carefully pour hot water over the duck to rinse. Discard the hot water; Place the duck on a rack in a roasting pan and dry the duck by patting it with paper towels, season the duck with salt and pepper and leave it in the roasting pan until ready to cook.
In a small bowl, mix the ingredients for the glaze together and brush all over the duck inside and out. Let it dry for about 10 minutes and then brush again. Repeat this process until you have used all but four to five tablespoons of glaze (reserve this glaze). Ideally let the glaze marinate on the duck overnight, leaving it uncovered in the fridge.
Preheat the oven to 180°C.
Place the duck in the oven and cook for 45 minutes. Turn the duck over, baste with the reserved glaze and cook for another 45 minutes. Cook until the skin is crisp and golden brown. Make sure you check halfway through that it is not getting too dark. If it is getting too dark before half the cook time is up, turn your heat down and lower the rack in the oven. When the duck is cooked, remove from the oven and let it rest while you make your sauce.
To make the sauce, in a small bowl, mix the cornstarch with one tablespoon of cold water and set aside. Next, heat a pan or wok and add the remaining sauce ingredients except the cornstarch mixture. When the sauce starts to bubble slightly, add the cornstarch mixture and stir well to thicken. Set aside and let it cool.
Slice some spring onions and cucumber into long thin strips.
Carve & slice some duck. Place a teaspoon of the sauce in the center of each pancake, add a couple tablespoons of duck, then garnish with spring onions and cucumber and serve immediately.