Trim all visible fat from the pork fillet. Cut the pork across into slices about 5cm thick, then cut each slice into thin strips.
Combine the ginger, garlic, sesame oil, soy sauce, sherry and vinegar in a bowl. Add the pork strips and toss to coat, then leave to marinate while you prepare the other ingredients.
Place the noodles in a large mixing bowl and pour over enough boiling water to cover generously. Leave to soak for about 4 minutes, or cook according to the packet instructions, until tender. Drain well and tip back into the bowl. Add the capsicum, carrot, spring onions and bean sprouts.
Drop the snow peas into a pan of boiling water and cook for about 1 minute or until just tender but still crisp. Drain and refresh under cold running water. Add the snow peas to the noodle and vegetable mixture and toss to mix. Set aside.
Toast the sesame seeds in a large frying pan over medium heat for 1–2 minutes or until golden, stirring constantly. Tip the seeds onto a piece of paper towel. Heat the sunflower oil in the frying pan, increase the heat slightly and add the pork with its marinade. Stir-fry for about 4–5 minutes or until the pork is no longer pink.
Add the pork and any cooking juices to the noodle and vegetable mixture, and stir gently to combine. Divide the pork and noodle mixture among 4 shallow bowls, sprinkle with the toasted sesame seeds and serve.