Boil the rice noodles according to the package instructions. Drain and rinse under cold water to prevent sticking.
While the noodles are cooking, prepare the vegetables by slicing the cabbage, carrots, and cucumber. Chop the cilantro and green onions.
In a bowl, whisk together peanut butter, soy sauce, rice vinegar, lime juice, maple syrup, sesame oil, and Sriracha (if using). Add water a little at a time to reach the desired consistency.
In a large mixing bowl, combine the cooked noodles, cabbage, carrots, and cucumber. Pour the peanut sauce over the top and toss to combine evenly.
Top with fresh cilantro, green onions, chopped peanuts, and sesame seeds if desired.
Enjoy immediately or refrigerate and serve chilled.
