Whisk yogurt, cucumber and dill, cover and set aside to cool. Cut meat into 2 1/2 cm strips, set aside. Heat oil in a large coated frying pan over medium heat for 2 minutes. Sauté onions for two minutes.
Add meat strips, garlic salt, and oregano; sauté or heat through 4 min, stirring occasionally. Cut warm pita bread almost in half, forming pockets. Fill meat, yogurt sauce and tomatoes evenly into pockets.
Tip: Use regular or light yogurt as needed!