In a large bowl mix together the dressing ingredients: lime juice, fish sauce and sugar. Add the zucchini, carrots and onions and toss gently. Then add the peanuts, basil, cilantro and mint and toss again just to combine.
Serve with Sriracha on the side.
Notes
Can use pickled onions or if you want to diminish the bite of the onions, slice them first and let them soak in the dressing.