Peel mango and slice into fine strips. Tip into a bowl with the prawns, spring onions and noodles. Put the coriander, mint, lime juice and zest, ginger, honey and fish sauce into a blender; blitz to form a smooth puree. With the motor still running slowly add the sunflower oil and finally the toasted sesame oil. Toss the salad with the dressing and finish with the sesame seeds and the coriander leaves.