Begin by cooking the rice vermicelli noodles according to package instructions. Drain and rinse under cold water to stop the cooking process. Set aside.
In a large bowl, combine the cooked noodles, shredded carrots, shredded red cabbage, cucumber, cooked shrimp, mint leaves, cilantro, green onions, and roasted peanuts.
In a separate small bowl, whisk together the fish sauce, lime juice, sugar, minced garlic, and red pepper flakes until the sugar is dissolved.
Pour the dressing over the salad mixture and toss gently to combine all ingredients evenly.
Serve immediately or chill in the refrigerator for about 30 minutes to allow the flavors to meld.