Make the batter:
Whisk together the batter ingredients and let stand for 15 minutes.
Cook the fish:
Heat the oil in a 4-quart pot or a wok until a deep-fat thermometer registers 375 degrees F.
While the oil is heating, cut the fish into 1/2- by 4-inch strips and toss with the salt. Place the flour in a wide, shallow bowl. Dredge the fish in the flour, then in the batter, and fry a few pieces at a time, until the batter is golden and the fish is just cooked through, 3 to 4 minutes. Transfer the fish to a paper-towel-lined plate to drain.
Make tacos with the accompaniments.
Mix together all the ingredients.
If you'd like to thin the sauce for drizzling, add a little water to the mixture.
Photograph by Romulo Yanes
If you have a wok for deep-frying, you can use less oil, 2 to 3 cups.
Reprinted with permission from Just Tacos by Shelley Wiseman, The Taunton Press copyright (c) 2011