Heat the oil in a large wok or frying pan on a medium heat. Pour in the egg, tilt the pan so it forms a thin omelette and cook for about 1 min until set. Tip out onto a chopping board, roll up, then slice into ribbons. Set aside.
Heat the curry paste with 1 tbsp water until hot, then tip in the rice, stir to break up and toss to coat.
Add the prawns and beans, and heat through. Add the lime juice and fish sauce, then stir though the egg strips. Serve the fried rice in bowls with extra lime wedges and fish sauce. Scatter with some sliced cucumber, chilli and coriander leaves, if you like.