Rub the inside and outside of the duck with salt and five-spice powder. Leave duck aside for one hour. Heat enough oil in a wok until hot, put in duck and deep-fry until lightly browned. Remove and drain from oil.
Heat 2 tbsp oil in a wok. Add all ingredients for the stuffing, seasoning, and toss toss ingredients well together.
Pack the entire cooked stuffing mixture into the cavity of the duck and close up the opening at its tail end with a needle and thread.
Place duck on a steaming tray and steam over rapidly boiling water for 50 minutes to an hour.
Remove duck and pour the liquid and juices from the steaming process into a small saucepan.
Thicken with corn flour mixture and then pour over the duck. Score the breast side of the duck and serve immediately.