To peel pomelo, slice off the top of the fruit, and score 4-6 deep line from the top to bottom. Peel the skin one section at a time. Remove pith and separate the segments of the fruit and crumble into big chunks discarding any visible seeds.
In a gentle simmering water, poach prawns until they curl up and turn pink.
In a large salad mixing bowl, combine pomelo, prawn, shallot, garlic, chilies, mint, cilantro, and coconut. Set aside.
In a small bowl whisk fish sauce, lime juice, and sugar together.
Just before serving, add the dressing over salad and toss to combine. Sprinkle peanuts on top.