To make dressing: place sugar and mandarin juice in screw top jar and shake to mix well until sugar dissolves. Finely grate ginger over a plate. Gather ginger pulp and squeeze ginger juice into jar, also adding any juice collected on plate, discarding the remaining ginger fibre. Add fish sauce to jar, replace lid and shake again to mix well.
Place chicken, bean sprouts, snow peas, carrot, apple, spring onion, chilli, mandarin segments, mint leaves and half of the sesame seeds in a large bowl. Pour over dressing and gently toss to combine. Scatter over remaining sesame seeds.
Serve salad with lettuce leaves on the side. To eat, pile salad into lettuce cups, using fingers wrap over edge of leaves either side to form a parcel. Enjoy.