Combine first 6 ingredients in a small bowl; stir well. Cover and chill.
Coat a large nonstick skillet with cooking spray; add lamb and onion, and cook over medium-high heat, stirring occasionally, 6 to 7 minutes or until lamb is done. Remove from heat; stir in Greek seasoning.
Divide lamb mixture evenly among 4 tortillas; top each evenly with cucumber sauce, tomato, and spinach. Roll up tortillas, and cut each wrap in half; secure with wooden picks, if necessary.