Cook noodles according to package directions and rinse with cold water to cool. Drain well. Drizzle with a tiny splash of toasted sesame oil to keep them from sticking until dressed.
Meanwhile, whisk sesame paste and peanut butter in the bottom of a small bowl, then whisk in soy sauce, rice vinegar, remaining 2 tbsp. sesame oil, sugar, ginger, garlic, and chile-garlic paste to taste until smooth. Adjust flavors to taste. It might seem a bit salty from the bowl, but should be just right when tossed with noodles.
Toss sauce with cold noodles.
Place a medium-sized knot of dressed noodles in each bowl, followed by a pile of cucumber. Garnish generously with peanuts and herbs. Serve with extra chile-garlic paste on the side.
