Cook the Noodles: Begin by filling a large pot with water and adding a generous pinch of salt. Bring the water to a rolling boil. Carefully add the soba noodles and cook according to the package instructions until tender but still firm (typically 4-5 minutes). Once cooked, drain the noodles and rinse them under cold running water to halt the cooking process and cool them down. Set aside.
Prepare the Dressing: In a medium mixing bowl, combine the sesame oil, soy sauce, rice vinegar, chili paste, peanut butter (or tahini), freshly grated ginger, and minced garlic. Whisk these ingredients together vigorously until smooth and well blended. For an extra kick, feel free to incorporate additional chili paste to taste.
Combine Noodles with the Dressing: In a large mixing bowl, add the cooled noodles. Drizzle the prepared dressing over the noodles and gently toss using tongs or large forks, ensuring that the noodles are evenly coated with the flavorful sauce.
Incorporate the Vegetables: To the bowl of dressed noodles, add the sliced green onions, julienned cucumber, and julienned carrot. Toss everything together thoroughly, making sure the vibrant vegetables are well distributed throughout the noodles.
Garnish and Serve: Carefully transfer the spicy sesame cold noodles to a serving platter or divide them among individual bowls. Lightly sprinkle toasted sesame seeds over the top and add a generous handful of fresh cilantro leaves for a burst of color and flavor.