Mix together the papaya, parsley, sugar, lime zest and juice. Add the chopped chilli and one of the small chillies, finely sliced. (This will make the salsa very hot so only add if you like it spicy).
Season with salt and pepper. Heat a large nonstick pan, add the oil and saute the prawns for just 3 minutes until they turn bright pink and the garlic is lightly golden. Stir in the lime zest and season.
To serve place a small handful of salad leaves on each plate, pile the prawns on top and drizzle the salsa over and around. Garnish with the spring onion and a small red chilli.