Beat together the eggs and chilli. Heat a little of the oil in a large non-stick frying pan and add an eighth of the egg mixture. Swirl the pan until completely covered and you have a very thin omelette. Cook for 2 minutes, then carefully turn and cook on the other side. Repeat to make eight wraps and allow to cool.
Combine the sugar, soy sauce, ginger, lime juice and mirin in a medium bowl. Add the spinach, spring onions, coriander, pepper, beansprouts and prawns and turn to lightly coat in the dressing. Divide the filling among the omelettes and roll up tightly. Cut in half to serve.