Remove the skin from the duck and discard it. Cut the breasts into thin strips. Heat the oil in a large frying pan or wok. Season the duck and fry for 2 minutes, stirring constantly. It should be medium-rare – if you prefer it more well done, cook for a little longer (if using chicken, make sure it is cooked through at this stage). Use a slotted spoon to transfer the meat to a plate.

Return the wok to the heat and add the onion, chilli, lime leaves and pepper. Stir-fry over a high heat for a few minutes until fragrant, then add the pak choi, chilli and ginger sauce and 
a little salt. Stir for another minute, then remove from the heat, stir in the sliced duck 
and add lime juice to taste. Finish with the coriander 
and serve immediately.