Cook the noodles according to the packet instructions (you can also get bags of ready-cooked ones these days). If you’ve cooked them yourself you need to shake the sieve that you drain them in, trying to get rid of as much water as possible. Toss the with the groundnut and sesame oil.
To make the dressing, pound the garlic, ginger and chilli in a mortar and pestle until they’re broken up (they don’t have to become a paste) then add the other ingredients.
Blot the prawns dry with kitchen paper. If they’re wet they will just steam instead of frying.
Get everything ready to assemble the salad.
Heat a film of groundnut oil in a large frying pan and cook the prawns in two batches (so as not to crowd the pan) over a high heat until they turn from grey to pink. It only takes a few minutes. Season and add the lime juice.
Toss the noodles with the vegetables, mango, herbs, prawns and dressing and serve immediately.