Mix the sauce ingredients together and set aside.
Place the flour, cornflour, coriander and a good pinch of salt and pepper in a large bowl. Using a fork, stir in the sparkling water to make a batter of the consistency of double cream. Do not overstir the batter: small lumps of flour are fine. Pat the fish strips dry on kitchen paper and dip into the batter.
Pour the oil into a deep-fat fryer or large saucepan to a depth of at least 7 cm (3 inches) and heat to 180–190°C (350–375°F), or until a cube of bread browns in 30 seconds. Cook the fish in small batches until it is golden brown. Drain on kitchen paper and keep warm while you cook the remainder.
Serve the goujons with the sauce, garnished with the lime wedges.