Rinse prawns in salt water, then rinse again in clear water. Soak up moisture with kitchen cloth, then marinade for 20 minutes.
Heat oil in wok until very hot, add in prawns and deep fry for 1/2 a minute. Pour out oil and prawns, leaving 1tbsp oil in wok. Fry chili, minced scallions and ginger, then add wine.
Put in prawns again and stir until well combined, add 1/2tsp salt and stir again, then serve.