Fill a Dutch oven halfway full with oil and heat to 350 degrees F.
Add the cornmeal, flour, baking powder and salt and whisk to combine in a large bowl. Whisk in the beer, being sure to remove any lumps. Stir in the hot sauce.
Sprinkle the fillets with salt and pepper. Dip each fillet in the beer batter and add to the fryer, one at a time. Fry until brown and crispy, 3 to 4 minutes, flipping halfway through. Transfer the fillets to a wire rack on a baking sheet and sprinkle with salt and pepper. Repeat with the remaining fillets.
Spread the Lemon Tarragon Tartar Sauce on the bottoms and tops of the rolls. Add the fillets and top with some lettuce. Serve with lemon wedges.
Fold together the mayonnaise, pickles, scallions, capers, tarragon, mustard, lemon zest, lemon juice in a bowl and sprinkle with salt and pepper. Adjust the seasoning to taste. Cover the bowl and refrigerate until ready to serve, about 20 minutes.