Soak the noodles: Place vermicelli noodles in a heatproof bowl and cover with just-boiled water. Soak for 5–7 minutes until tender. Drain, rinse under cold water and cut into shorter lengths if needed.
Make the dressing: Whisk all ingredients together until the sugar dissolves. Taste and adjust the balance — it should be bright, salty, sweet and just the right amount of spicy.
Assemble the salad: In a large bowl, combine the shredded chicken, noodles, cabbage, carrot, bean sprouts, shallots, coriander and mint.
Dress and toss: Pour over the dressing and toss well to combine.
Serve: Transfer to a platter or serving bowl. Sprinkle with roasted peanuts and crispy fried shallots just before serving.