Heat olive oil in a large skillet over medium heat. Add finely chopped onion and sauté for 3-4 minutes until softened.

Stir in minced garlic and sauté for 30 seconds until fragrant.

Add ground beef, breaking apart with a spoon. Stir in cumin, oregano, paprika, salt, and pepper. Cook for 5-7 minutes until browned.

In a medium bowl, whisk together Greek yogurt, lemon juice, minced garlic, olive oil, and salt until smooth.

Warm pita breads in a dry skillet over low heat for 1-2 minutes on each side.

Assemble each pita by filling with cooked beef, chopped tomatoes, sliced cucumbers, and parsley.

Drizzle yogurt sauce over the filled pitas and serve warm.