1 large unpeeled European cucumber—halved lengthwise, seeded and cut into
1 red bell pepper, finely chopped
Bring a large saucepan of salted water to a boil. Add the soba noodles and cook over high heat, stirring occasionally, until al dente, about 5 minutes. Drain and let cool under cold running water, then drain again.
In the same saucepan, combine 2 quarts of water with the bay leaves, peppercorns and 1 tablespoon of salt. Squeeze in the juice from the lemon, add the lemon halves and bring to a boil. Add the shrimp and cook over moderately high heat until pink throughout, 3 to 4 minutes. Drain the shrimp and plunge them into a bowl of ice water to cool. Drain the shrimp again and pat dry.
In a small bowl, combine the rice vinegar with the miso, sugar and sesame oil. Whisk in the canola oil and season with salt and pepper. Stir in the pickled ginger. Toss the shrimp with 1/4 cup of the dressing. In a large bowl, gently toss the noodles with the scallions, cucumber and bell pepper. Add the remaining dressing and toss gently to coat. Transfer the soba salad to a platter and top with the shrimp.
The recipe can be prepared up to 1 day ahead. Refrigerate the soba noodles, shrimp and dressing separately. Toss together and serve at room temperature.