Heat the wok until very hot, add the oil and swirl to coat.
Stir-fry the prawns, garlic, ginger, chilli and cilantro root in two batches for 1-2 minutes over high heat, or until the prawns turn pink. Remove all the prawns from the wok and set aside.
Add the spring onion and capsicum to the wok and cook over high heat for 2-3 minutes, then add the lemon juice, wine & palm sugar.
Cook until the liquid has reduced by two thirds, add the prawns, sprinkle with fish sauce and toss to heat through.
Garnish with the coriander (cilantro) leaves and serve.