In a small bowl, combine the spices to make the spice rub
Pat fish fillets dry and season well on both sides with kosher salt and black pepper, then rub all over with the spice rub. Set aside for now.
Prepare the lemon basil sauce. Simply combine all the ingredients for the sauce in a small bowl or mason jar. Whisk well together. Set aside.
If serving this grilled fish gyro-style, prepare the pita etc. Prepare Tzatziki sauce according to this recipe, and prepare the Mediterranean salad according to this recipe. Set aside for now.
Coat the bottom of a large cast iron skillet (or a non-stick skillet) with extra virgin olive oil. Warm skillet over medium-high heat until the oil is just shimmering but not smoking.
Add fish fillets and grill on one side for about 3 minutes or so without moving it (the underside should look golden and crispy). Then, using a fish spatula, turn it over to the other side (it should release easily from the pan). Grill for another 3 minutes or until this side turns nice and crispy as well. (You'll know your fish is ready when it turns opaque all the way through and flake apart easily.)
Serve fish hot. Add a splash of fresh lemon juice on top and a generous drizzle of the lemon basil sauce.
To assemble grilled fish gyros, use 1 pita wrap (or large lettuce leaf) per person. Swipe a bit of tzatziki sauce over the pita, add the grilled fish and lemon basil sauce, then add a bit of the Mediterranean salad and olives to your liking. Wrap or fold pita and enjoy!