Heat the oil in a frying pan or wok over high heat. Add the beef in 2 batches and cook for 5 minutes or until well sealed. Set aside. Add the chilli sauce, lime juice, spring onions and lime leaves to the pan and cook for 4 minutes, then pour over the beef.
To make the salad, place the noodles in a saucepan of boiling water and cook for 2 minutes or until tender. Drain and rinse under cold water. Combine the noodles with the cucumber, celery and lettuce and place on serving plates. Top with the beef mixture and serve with lime wedges. Serves 4.