Boil the noodles and blanch the edamame.
Bring a pot of salted water to a boil. Add the soba noodles and cook according to the package until soft but still chewy (about 4–6 minutes for many brands; your pack may say 5–7). Add the frozen edamame during the last minute to blanch. Drain and rinse both under cold water until cool. Shake off excess water.
Make the sauce.
Whisk 2 tsp sesame oil, 2 tsp soy sauce, 2 tsp lime juice, 2 tsp chili crisp, 1 tsp maple syrup, and 1 tsp white miso in a small bowl. Taste and adjust: add more lime if you want brightness, or more chili crisp if you like it spicy.
Prep the veggies.
Mandoline the cucumbers on the thinnest setting. Toss the ribbons with a small pinch of salt and let them sit briefly to release excess water, then pat dry with paper towels. Slice scallions and chop cilantro.
Toss everything.
Place the cooled noodles and edamame in a large bowl. Add the cucumbers, scallions, cilantro, and chopped nuts (if using). Pour 2–3 tbsp of the dressing over everything and toss until evenly coated. Top with a sprinkle of toasted sesame seeds.
Serve chilled.
Plate the bowl cold or at room temperature. Add more dressing as needed. Enjoy immediately.