1. Trim excess fat from duck. Immerse duck in boiling water. Add leek, wine and ginger and boil for 1 1/2 minutes. Remove duck and set aside.
2. Combine fruit sauce ingredients in a bowl; mix well.
3. Place duck in a casserole dish; add fruit sauce. Cover and bake in a preheated oven at 375°F (190°C), for 1 1/23 hours.
4. Discard lemon and orange slices. Transfer duck to a platter. Thicken 1/2 cup of leftover sauce with 1 teaspoon cornstarch and pour over duck. Garnish with extra orange slices.