Whisk the eggs with 2 tbsp water. Heat 1 tbsp of the oil in a large non-stick frying pan. Swirl the eggs into the pan and cook for 2 mins until set, flip over and continue to cook for 1 min. Tip the omelette onto a board and, when cool enough to handle, slice into strips and set aside.
Heat the remaining oil in a large wok and stir-fry the chicken for 5 mins until browned, then add the ginger and garlic, and cook for a few mins. Scatter over most of the spring onions, reserving some to sprinkle on the top, followed by the sake or sherry and noodles. Give everything a good mix. Drizzle over the soy, stir through the shredded omelette, sprinkle over the reserved spring onions and serve.