Mix all of the ingredients in a medium bowl and set aside in the fridge to chill.
Fish Fillet Sandwich
Line a baking sheet with foil and place it in the oven. Preheat to 350 degrees F for 30 minutes.
Set up a dredge station using 2 shallow bowls or pie plates. Mix the flour, bread crumbs, garlic powder, salt, and pepper in the first bowl. In the second bowl, beat the eggs.
Dip the tilapia in the egg and allow the excess to drip off. Then place the fish into the flour mixture and coat both sides completely. Shake off any extra breading.
Coat the tops of the fish with non-stick cooking spray or olive oil spray. Then carefully place the fish, oil side down, on the hot baking sheet. Coat the top of each fillet with more spray.
Cook for 15 minutes. Then flip and cook another 15 minuntes or until fish is cooked through and the crust is golden brown.
Separate the buns and place them cut sides up on another baking sheet. Add 1 slice of cheese onto the bottom half of each bun. Place in the oven until the cheese is melted and the buns are toasted.
To assemble: Place a tilapia filet on each bottom bun. Top with some tartar sauce and some shredded lettuce before adding the top bun. Serve immediately.