Bring a half cup of water to a boil in a medium saucepan; add the frozen peas, bring to a boil, and simmer for 4 minutes (do not overcook); drain, and set aside.
In a large bowl, combine the cooked chicken, cooked peas, tomatoes, feta cheese, green onion and black pepper if desired.
Fold in the yogurt, mayo, lemon juice and dillweed; toss well to combine.
Line the pita halves with a leaf of lettuce or shredded lettuce if desired, and stuff with chicken mixture.
If you are a garlic lover, then fresh garlic or garlic powder may be added to the mixture.