1.Preheat oven to moderate, 180°C. Line a baking dish with foil or baking paper.
2.Rub combined salt, sugar, szechuan pepper and five spice over skin and cavity of duck. Place ginger, garlic and onion into cavity. Transfer to dish and bake 1 1/2 hours, basting with juices every 20 minutes.
3.Increase oven to very hot, 220°C. Bake a further 15-20 minutes, basting once, until skin is crisp and golden.
4.Remove from oven and rest, covered loosely with foil, 15 minutes. Remove duck breast and remaining meat with skin attached. Slice thinly.
5.Make Dressing; in a small jug, whisk all ingredients together.
6.Make Salad; in a large bowl, combine all ingredients.
7.Drizzle salad with half dressing, tossing to coat, Add duck and drizzle with remaining dressing to serve.