Place cucumber in a mini food processor or grate with a box cheese grater. Drain the liquid from the cucumber in a metal strainer and use the back of a spoon to help squeeze out any excess liquid.

Combine the grated cucumber with Greek yogurt, garlic, lemon juice, mint, dill, salt, and pepper. Refrigerate until ready to eat.

Season the fish with 0.5 teaspoon of salt and cut into 8 strips.

Place flour on a plate, and the beaten egg in a shallow bowl. On another plate, combine panko crumbs with the remaining 0.5 teaspoon salt, garlic powder, and oregano.

For the Air Fryer Method: Preheat the air fryer to 400°F. Coat the fish pieces first in the flour (shaking off excess), then dip into the egg, and finally coat with the panko mixture. Place coated fish onto a board lined with parchment or wax paper. Spray both sides of the fish with olive oil spray. Transfer the fish to the air fryer basket in a single layer. Cook for 4 minutes, flip, and cook for an additional 2 to 3 minutes, until golden and crisp.

For the Oven Method: Preheat the oven to 425°F. Coat the fish pieces first in the flour (shaking off excess), then dip into the egg, and finally coat with the panko mixture. Place coated fish onto a board lined with parchment or wax paper. Spray both sides of the fish with olive oil spray. Transfer to a baking sheet in a single layer. Bake for 5 to 6 minutes, flip, and bake for another 5 to 6 minutes, until golden and crisp.

To serve, place about 1/4 cup of chopped cabbage over each warm tortilla. Top with a piece of cooked fish, a spoonful of tzatziki sauce, diced tomatoes, and diced red onion. Squeeze fresh lemon juice over everything before serving.