Sesame-Peanut Noodles

Bring a large pot of salted water (figure about 1 teaspoon salt per quart of water) to a boil.
Meanwhile, toast the sesame seeds in a dry skillet over medium heat, stirring or shaking things frequently, until they turn golden brown, about 5 minutes. Transfer to a plate to cool.
In a food processor, combine the peanut butter, sesame oil, peanuts, soy sauce, vinegar, mirin or sherry, garlic, and red pepper flakes. Process to a purée. Stir in half the cooled toasted sesame seeds.
Slice the cucumber in half lengthwise and use a spoon to scoop out the seeds and toss them in the compost or the trash. Slice each cucumber half crosswise about 1/4 inch thick.
Add the noodles and cook until tender, 4 to 5 minutes. Drain very well, shaking the colander until it stops dripping, and dump into a bowl. Add the peanut mixture, cilantro, and black pepper, and toss to coat. Turn out onto a large platter. Arrange the cucumber slices around the edge of the platter, sprinkle the scallions on top, and sprinkle the remaining sesame seeds on last. Serve warm or at room temperature.