Cut each fillet in half lengthwise. Cut each half on a diagonal into 2” strips. (Work with the natural shape of the fish as you cut; this will help the pieces stay together instead of falling apart when frying.)
Whisk all-purpose flour, rice flour, and salt in a medium bowl. Gradually whisk in club soda until no lumps remain; adjust with more club soda or rice flour as needed to make it the consistency of thin pancake batter—it should be pourable, but thick enough to coat the fish.
Pour oil in a large cast iron skillet (my favorite for frying) about 1" deep, heat over medium high heat . Working in batches of 5–7 pieces at a time, coat fish in batter, letting excess drip off, then carefully place in oil (to avoid splattering, lower fish into oil pointing away from you). Don’t overcrowd the pot: The oil temperature will drop dramatically and fish may stick together.
Fry fish, turning occasionally with a fish spatula or slotted spoon until crust is puffed, crisp, and golden brown, about 5 minutes. Transfer to a plate lined with paper towels; season immediately with salt.
Meanwhile, warm your tortillas- either wrap up a stack of tortillas in a sheet of foil and heat in a 350° oven until warmed through, or hit them for 30 seconds in the microwave.
In a large bowl, whisk together the sour cream, herbs, lime juice, and lime zest. Whisk in mayonnaise and season with salt and pepper. Add cabbage and scallions, toss to coat.
Top tortillas with fish, slaw, hot sauce, avocado, cilantro, and peppers. Serve with lime wedges.