Boil the noodles for three minutes or until done. Drain and rinse in cold water. Pour a small amount of sesame oil over the noodles and mix in with your hands. Set aside.
Beat the eggs, add salt or soy sauce, and make several thin omelettes, using a little neutral oil to coat the pan lightly. Allow to cool, cut into quarters, and slice in thin strips. Prepare the vegetables, ham, and crab. Set aside.
Combine the sauce ingredients and, if time permits, chill for an hour or more.
To serve, pile some noodles onto four deep-rimmed plates and arrange the other ingredients on top to look like a slice of pie, working from the center out. Pour sauce over the top and sprinkle with liberally with sesame seeds . Pass the pickled ginger and mustard separately.