In a medium bowl, combine the peanut butter, soy sauce, maple syrup, rice vinegar, and chili garlic sauce. Whisk until smooth.

Bring a large pot of water to a rolling boil. Add rice noodles and cook according to package instructions for 4-6 minutes, then drain and rinse under cold water.

In a large mixing bowl, add the drained noodles and pour the peanut sauce over them. Toss gently with tongs until evenly coated.

If using vegetables, stir in sliced bell peppers and shredded carrots until evenly distributed.

Transfer to serving bowls and garnish with toppings like crushed peanuts, green onions, or cilantro.