For the chilli beef, heat a deep-fat fryer to 190C/375F or heat the oil in a deep heavy-based frying pan until a breadcrumb sizzles and turns brown when dropped in. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
In a pestle and mortar, crush the Sichuan peppercorns to a fine powder. Place them in large bowl with the lime and orange zest and rice flour then toss well to combine. Toss the beef strips in 2 tablespoons of vegetable oil. Add the beef to the spices and toss to coat each piece thoroughly.
Deep-fry the beef in batches, cooking each for about 2 minutes, or until crisp. Drain on kitchen paper.
For the sauce, heat a frying pan or wok until hot, add the sugar, rice wine and rice wine vinegar and bring to the boil. Add the chillies, chilli flakes, ginger, lemongrass and lime leaves then cook for 5-8 minutes until thickened, sticky and glossy looking. Add the cooked beef to the sauce, remove from the heat and toss well so that all the beef is coated in sticky chilli sauce.
For the sticky rice omelette, heat a wok until hot, add the oil and swirl to coat it.
Whisk the eggs and soy sauce together, then pour into the hot wok, lifting the wok up and rolling the egg around the sides of it so you have one very large omelette. Add the cooked rice to the centre of the omelette then carefully peel the omelette away from the sides of the wok and fold over the rice. When the rice is hot through and the omelette set, roll out onto a board and cut into four pieces.
To serve, pile the beef onto plates and the rice omelette in separate bowls.