Toss the cucumbers with 1/2 teaspoon sea salt and 1 tablespoon rice wine vinegar and set aside.
In a large bowl, toss buckwheat noodles with almost all of the sauce until well combined. Spoon into serving bowls, top with cucumbers, green onions, and cilantro. Finish with a final drizzle of sauce and sesame seeds.
If you plan to serve and eat the noodles all at once, feel free to toss all the ingredients together just before serving. Otherwise, keep the cucumbers and noodles seperate until just before you serve.
Noodles will keep well in the fridge for two days.