Begin by boiling water in a large pot. Once boiling, add the rice noodles and cook according to the package instructions, usually about 4–6 minutes. Drain the noodles and rinse them with cold water.

In a medium-sized bowl, combine peanut butter, hoisin sauce, lime juice, soy sauce, and water. Whisk together until smooth, adjusting consistency as needed.

In a large bowl, combine the cooled rice noodles, cucumber, purple cabbage, carrots, and red bell pepper. If using, add chopped cilantro and mint. Toss gently to mix.

Drizzle the peanut sauce over the salad and toss gently until well coated.

Transfer to serving bowls and serve immediately or chill for 10 minutes before serving. Garnish with chopped peanuts.