1. For the black pepper sauce,toast the peppercorns in a pan over a medium heat for 1 minute,then grind roughly using a mortar and pestle,and reserve.
2.Pound the garlic and chilli using a mortar and pestle. Fry in oil in a wok over medium heat until fragrant (about 30 seconds),add peppercorns and fry,until almost smoking,for a further 30 seconds to 1 minute.
3. Add the sauce's remaining ingredients except the cornflour-and-water mix,and simmer until thickened slightly – about 2 minutes. Add cornflour mix slowly,until desired consistency is achieved (this will be dependent on the strength of their stove).
4. Preheat barbecue or grill pan on medium-high. Place prawns in a bowl,season,drizzle over oil,and toss to combine. Grill for 2-3 minutes,then turn over. Cook until the prawns turn opaque,red and just cooked.
5. Place prawns on a large platter,top with the pepper sauce,and garnish with ginger,chives and coriander.
Tip: Add a green base to this dish:stir-fry a couple of bunches of water spinach in a wok with a little oil,garlic,water,sea salt and white pepper,and top with oyster sauce and bird's-eye chilli slices.