- Preheat the oven to 190°C/170°C fan/Gas 5.
- Place the duck legs on a baking tray, season with salt, then cook in the oven for 2 hours until tender and crispy.
- While the duck legs are cooking, make the dressing. Put the ginger into a bottle or jar with the lemongrass and chilli halves. Pour the lime and lemon juices into the bottle, add the soy sauce and olive oil, season with salt and pepper, then put the lid on and shake the bottle well. Leave to infuse until you are ready to serve. Strain before using.
- When the duck legs are completely crispy, remove from the oven and leave to cool. Once they are cool enough to handle, pick the meat from the bones, discarding any soft fat. Use two forks to do this – the meat should come away from the bones very easily. Place the picked meat in a bowl.
- Mix the orange juice, tomato ketchup, honey, soy sauce and sesame oil together in a bowl. Add this sauce to the shredded duck and stir through until well mixed.
- Combine the watercress, chillies, ginger, daikon and radishes in a separate large serving bowl, add the salad dressing (minus the aromatics) and toss to mix. Add half of the coriander leaves, spring onions and toasted sesame seeds and toss to mix.
- Serve the salad on a platter or individual plates with the crispy duck on top, then sprinkle with the remaining coriander, spring onions and sesame seeds.