Marinate squid for about 30 minutes in fish sauce or soy sauce and sugar.
Grind coriander roots with salt and peppercorns in a mortar. Add garlic and grind to coarse paste, removing some of the excess skins, center shoot and hard base.
Mix paste with garlic. Heat enough oil in a wok and deep-fry squid and garlic in it at high temperature, stirring continuously, until golden brown. Then remove and drain, do not overcook the squid – perhaps remove garlic and squid separately. Sprinkle with cilantro and bring to table with a bowl of chili sauce (next recipe).