Preheat the oven to Gas Mark 2, 150°C, fan 130°C. Scatter the desiccated coconut on a baking tray and roast for
3 minutes, until lightly toasted. Set aside to cool.
Divide the grapefruit, avocado, prawns and shallot between four plates and scatter over the chilli, mint, coriander and coconut. Combine the dressing ingredients in a jug and mix with 1 tbsp water until well combined. Drizzle the dressing over the plates of salad just before serving.