Buckwheat Noodles, Mizuna (or Mibuna), and Radishes with Tart Tofu-Mizuna Dressing

Cool and satisfying on a summer’s eve: taupe soba noodles, sharp emerald mizuna, and scarlet radishes are dressed with a thick, smooth, lemony dressing. Choose the smallest mizuna so the pretty lacy leaves (not stems) can star. Or substitute mibuna. The weight of soba noodle packages varies—use whatever is close to ¾ pound. If roasted peanut oil is not in your pantry, substitute 1½ tablespoons vegetable oil plus 2 teaspoons Asian (dark) sesame oil.