To make the spiced salt, heat a small frying pan over medium-high heat and add the salt. Stir for 30 seconds, just to warm, and remove from the heat. Transfer to a small mortar and pestle, and add the pepper to crush, mixing well.
Combine all the batter ingredients and half a cup of cold water in a large bowl. Dip the squid pieces in the cornflour and sprinkle with half the spiced salt, then add squid to the batter.
In a wok with a thermometer on the side, heat the oil to 180 degrees. Gently place the squid in the hot oil and move around with chopsticks to stop the pieces from sticking together. Fry for a couple of minutes until golden brown, remove from the oil and place on a plate with kitchen paper to drain.
Quickly but carefully pour the oil off into a stainless-steel container, place wok back on the heat and add two tablespoons of oil, add the garlic, ginger and spring onion and fry for a moment then add the drained squid and toss around with remaining salt. Remove from the wok to a plate and garnish with sprigs of coriander.