Place a large non-stick skillet over medium-high heat.
Add ground beef and diced onion to the skillet and cook for 7-10 minutes, breaking up the meat with a spatula, until fully browned.
Drain any excess rendered fat from the skillet using a spoon or colander.
Lower heat to medium and stir in minced garlic, cumin, coriander, paprika, cinnamon, salt, and pepper.
Sauté for an additional 2 minutes until the spices are toasted and fragrant.
Remove the skillet from heat and fold in the chopped fresh parsley.
Warm the pita bread halves in a low oven or microwave for 15 seconds to increase pliability.
Open each pita pocket and layer in shredded lettuce, diced tomatoes, and diced cucumbers.
Evenly distribute the spiced beef mixture among the eight pita halves.
Garnish each pocket with a dollop of hummus or Greek yogurt and serve immediately.