In a medium bowl, combine the peanut butter, soy sauce, maple syrup, lime juice, sesame oil, chili oil or hot sauce, and garlic.
Add 1/4 to 1/2 cup water, 1 tablespoon at a time, and whisk until the sauce is a pourable consistency.
Taste and add more chili oil or hot sauce as desired; set aside.
Cut the zucchini or cucumber and radishes into 1/8-inch thick slices, then cut into thin matchsticks.
Slice the peppers into 1/8-inch pieces.
Place all vegetables in a large bowl.
Loosen the soba noodles by running them under some water; allow to drain again.
Add noodles to the vegetables; add the remaining 1 tablespoon sesame oil and toss to combine.
When you are ready to serve, drizzle with spicy peanut sauce and top with peanuts, scallions and cilantro.
Serve immediately, with lime wedges alongside.