Press cucumber between layers of paper towels to remove excess moisture. Combine cucumber, yogurt, seasoned salt, and dillweed; cover and chill.
Cook meat, chopped onion, and garlic in a large nonstick skillet over medium-high heat until meat is browned, stirring until it crumbles. Drain, if necessary. Stir in 1/4 teaspoon salt and pepper.
Combine tomato and green onions. Line each pita half with a lettuce leaf; top evenly with meat mixture, cucumber mixture, and tomato mixture.