For the chilli beef, heat the oil 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 leave unattended.) Alternatively, heat a deep fat fryer to 190C.
In a bowl, coat the beef strips in the two tablespoons of vegetable oil.
Heat a frying pan until hot, add the Sichuan peppercorns and dry fry for one minute, or until fragrant. Transfer to a pestle and mortar and crush until coarsely ground, then add the orange zest and crush again until well combined.
In a bowl, mix together the salt, rice flour and Sichuan pepper and orange zest mixture until well combined.
Add the beef strips and mix well to coat them in the mixture. Discard the remaining flour and Sichuan pepper mixture.
Carefully lower the coated beef strips into the hot oil in batches and fry for 2-3 minutes, or until crisp and golden-brown. Remove from the pan using a slotted spoon and set aside to drain on kitchen paper. Repeat the process with the remaining beef strips.
Carefully lower the carrot strips into the hot oil and fry for 1-2 minutes, or until just softened (they should float to the surface of the oil when ready).
Remove from the pan using a slotted spoon and set aside to drain on kitchen paper. Repeat the process with the remaining carrot strips.
For the sauce, heat a non-reactive frying pan over a medium heat. When the pan is hot, add the rice wine vinegar, sugar and soy sauce and bring the mixture to the boil.
Add the chillies, chilli flakes and grated ginger and cook for 2-3 minutes, or until the mixture is sticky and has thickened.
Add the fried beef and carrot strips and cook for 1-2 minutes, stirring well to combine.
Meanwhile, for the noodles, heat the vegetable oil in a wok over a high heat. When the oil is smoking, add the ginger, garlic and spring onions and stir fry for 2-3 minutes, or until softened. Add the cooked noodles and stir fry for a further minute, or until warmed through.
Add the sesame oil, soy sauce, rice wine vinegar and lemon juice and mix well to combine.
Add the sesame seeds and stir fry for a further 1-2 minutes.
Sprinkle over the coriander and stir well to combine.
To serve, divide the stir-fried noodles equally among four serving plates. Spoon over the chilli beef strips in the sauce.