Prep: 1. Slice red onion. 2. Open pitas by slicing about 1 inch off the top (or in half depending on size), and carefully peeling apart the sides. Make: 1. Mix ground beef, oregano, salt and pepper. 2. Form into 1-2 inch meatballs or patties depending on taste. 3. Heat 1 tablespoon of the oil in a large skillet over medium heat and cook the patties, 2-3 minutes per side. 4. Fill the pitas with the hummus, patties, onion, and spinach. Drizzle with the remaining tablespoon of oil. 5. Serve.