Using kitchen scissors, halve duck lengthways and press to flatten. Remove fat from inside tail, clean cavity and cut off tail. Rinse under cold running water and pat dry with absorbent paper.
Combine sea salt with Sichuan pepper in a frying pan and stir over medium heat for 4-5 minutes or until fragrant. Place mixture in a mortar and, using a pestle, coarsely grind, then stir through five spice. Rub half the mixture evenly all over duck and place in a ceramic dish, cover with plastic wrap and stand at room temperature, turning once, for 6 hours or refrigerate for up to 2 days.
Remove duck from marinade, then rub with rice wine. Coarsely crush ginger and green onion and rub evenly over duck. Place duck in a roasting pan large enough to snugly fit duck.
Place a large bamboo steamer over a waterfilled wok and bring to the boil over high heat, reduce heat to medium, add duck tray and steam, replenishing water and removing liquid from duck tray every 30 minutes, for 3 hours or until tender.
Place duck on a wire rack over a tray and leave in a draughty place to dry for 2 hours. Heat oil in a large, heavy-based saucepan or deep fryer to 190C. Rub duck with soy sauce and dust with plain flour. Deep fry for 3-4 minutes or until crisp, remove and place on an absorbent paper-lined plate. Increase heat to 200C, return duck and deep fry for 30 seconds or until dark brown.
For cucumber salad, cut cucumber crossways into 1cm crescents and combine with Sichuan pepper, sugar and chilli oil and season to taste with sea salt and freshly ground black pepper. Serve duck sprinkled with remaining salt mixture, roasted peanuts, cucumber salad and steamed rice.
Note Chilli oil is available from Asian
supermarkets and grocery stores.