Nice pork souvlaki sandwich, serve with Greek salad.
Whisk together lemon juice, olive oil, garlic, oregano, salt, and pepper in a large bowl. Add pork and stir to coat. Let marinate for at least 10 minutes.
Heat a skillet over medium-high heat. Drain and discard excess marinade from pork. Cook pork in the hot skillet until cooked through and juices run clear. An instant-read thermometer inserted into the centers should read at least 145 degrees F (63 degrees C).
Spread tzatziki sauce over each pita round. Divide feta cheese evenly among pitas. Divide pork among pitas. Sprinkle each pita with sliced tomatoes. Fold pitas over and serve.
Per Serving: 438 calories; protein 28g; carbohydrates 34g; fat 43.8g; cholesterol 77.1mg; sodium 782.1mg.