In a bowl, mix half the finely chopped garlic, 1 tbsp fish sauce, 1 tbsp lime juice, salt, and pepper. Rub this mixture over the chicken thighs and set aside to marinate for 10 minutes.
Heat a frying pan or BBQ plate to a medium-high heat. Cook the chicken thighs for 5-7 minutes each side, or until cooked through and golden. Once cooked, let them rest briefly then thinly slice.
To make the dressing: Whisk together the remaining fish sauce, lime juice, rice vinegar, caster sugar, and remaining garlic until the sugar dissolves.
In a large bowl, combine the cooked vermicelli noodles, sliced cabbage, cucumbers, carrots, spring onion, coriander, and mint.
Add the sliced chicken and the dressing to the bowl. Toss gently to combine.
Divide the salad among serving plates and top with the fanned avocado slices and chopped toasted peanuts.
4 servings