Soak the noodles in boiling water for 5 minutes, then drain and set aside in a large bowl.
To make the dressing combine all the ingredients into a bowl and set aside until the sugar has dissolved.
Prepare the vegetables – cut the carrot and cucumber into fine matchsticks, slice the spring onions thinly and diagonally, peel and chop the mango into slices and finally pick the coriander leaves and finely chop the chilli.
Add the vegetables, mango, coriander and chilli to the noodles. Pour over the dressing, toss everything together until fully combined.
Plate up and sprinkle over the crushed peanuts and serve with sliced beef.