Prawn Rice Noodle Salad

    * 250g pack thin rice noodles
    * 1 mango
    * 200g peeled prawns
    * bunch spring onion ,sliced
    * 20g pack coriander ,chopped

For the dressing :

    * 2 rounded tbsp crunchy peanut butter
    * 1 tbsp light muscovado sugar
    * good pinch chilli powder
    * 2 limes ,juiced
    * Salt as required .