Bring a large covered pot to a rapid boil. Blanch the snow peas, uncovered, for a minute, until tender but still bright green. Remove the snow peas with a slotted spoon or a strainer, place them in a large serving bowl, and set aside. Cook the noodles in the same water until just tender, about 3 minutes. Drain, rinse under cold water and drain again.

While the pasta cooks, prepare the sauce: In a small bowl dissolve the miso in the water. Whisk in the apple juice, sesame oil, soy sauce, ginger, and vinegar. Chop the scallions.

In the serving bowl, toss the snow peas, sauce and scallions with the noodles.