Pound lemongrass, salt, and sugar into a paste, then add garlic, coriander, peppercorns, and fish sauce.
Rub the chicken with the paste and marinate in the refrigerator for two hours.
Preheat a grill pan or barbecue until hot.
Grill the chicken away from direct heat to impart smoky flavor and caramelize the marinade.
Turn pieces every three minutes and cook for 15 minutes until juices run clear.
Dry-roast nuts in a pan over medium heat until golden brown, then cool.
Grind ginger, chillies, shallots, and roasted nuts into a paste, then mix with sugar, soy, and tamarind.
Heat vegetable oil in a deep pan for frying.
Fry bean curd for 5 minutes until golden, drain, and cut into 0.5cm slices.
Blanch mangetout and sprouts for 30 seconds, refresh in cold water, and mix with remaining vegetables and bean curd.
Spoon dressing over the salad and serve alongside the grilled chicken.