juice of 1/2 lemon, plus additional wedges for squeezing
4 white or wheat pitas
1/2 red onion, thinly sliced
1 tomato, thinly sliced
1 medium cucumber, peeled and sliced + 1/2 teaspoon salt
2 cups cold plain Greek yogurt
4 teaspoons minced garlic
1/3 cup chopped dill, fresh or frozen (may sub 2 tablespoons dried dill)
1 1/2 tablespoons freshly squeezed lemon juice
1/2 teaspoon salt, or to taste
1/8 teaspoon black pepper, or to taste
Place steak, olive oil, garlic, oregano, salt, pepper, and juice from 1/2 lemon in a large resealable bag. Press excess air out and seal bag. Refrigerate for 1-8 hours.
Spread cucumber slices out on a paper towel. Sprinkle generously with salt on both sides and allow to rest for 5 minutes. Wrap cucumber slices in paper towels, squeeze excess liquid out, and transfer to a food processor or blender.
Add remaining sauce ingredients to blender and pulse until smooth and creamy. Cover and chill until ready to use.
Preheat grill, grill pan, or cast iron skillet, to medium-high heat. Use tongs to transfer steak to grill and discard excess marinade. Cook steak for 6-8 minutes on each side until desired doneness (I recommend leaving just a hint of pink in the center for super juicy, tender meat with lots of flavor!)
Transfer steak to a cutting board and allow meat to rest for a few minutes before slicing very thinly across the grain.
Assemble gyros with lettuce, sliced onions and cucumbers, and steak. Drizzle with tzatziki sauce, top with black pepper and fresh squeezed lemon and serve immediately.