Heat a deep-fat fryer to 190C or heat the sunflower oil for deep-frying in a deep, heavy-based frying pan until a breadcrumb sizzles and turns brown when dropped into it. (Caution: Hot oil can be dangerous. Do not leaves unattended.)
Put the Sichuan pepper in large bowl, add the lime and orange zests and the rice flour, then toss well.
Coat the beef strips with the vegetable oil, then with the peppercorn mix.
Deep-fry the beef in batches, for 2 minutes per batch, then drain on to kitchen paper.
For the sauce, heat a frying pan or wok until hot. Add the sugar, rice wine and vinegar and bring to the boil. Add the chillies, chilli flakes, ginger, lemongrass and lime leaves, then cook for 5-8 minutes, or until thickened, sticky and glossy.
Add the cooked beef to the sauce, remove from the heat and toss well so it is coated in sauce.
For the egg-fried rice, mix the eggs and sesame oil together in a bowl using a fork. Heat the groundnut oil in a wok until hot, then add the rice and stir-fry for 2-3 minutes, or until hot through. Add the eggs and stir-fry for 2-3 minutes more, or until set and the mixture is dry.
Season with salt and pepper and stir-fry for 2 minutes more, then stir in the spring onions, soy sauce and coriander. Serve the rice in bowls with strips of beef on top.