Heat the oil in a non-stick frying pan or wok over a high heat. Add the onion and fry for 5 mins. Stir in the snow peas, corn, pak choi and spring onions and cook for 5 mins more. Add the garlic, curry powder and soy sauce, and cook for another minute.
Add the udon noodles along with the ginger, and stir in 2-3 tbsp hot water until the noodles are heated through. Divide between bowls and serve.