Sauce:
Bring lightly salted water to a boil and cook soba or udon noodles according to package instructions. While water is coming to a boil, in a small saucepan, sauté the sweet onion until translucent, about four minutes. In a blender, blend all ingredients except for green onions. Drain noodles, and toss with sauce and fresh green onions. Makes 4 servings as a side dish.