Mix yogurt, cream cheese and first 4 dried spices until well blended. Spread dip in shallow glass casserole dish or pie plate. Cover and let sit in refrigerator for a few hours if you can.
Carefully open the pita breads and cut into triangles, and place on two baking sheets spraying both sides with olive oil spray (or brush a small amt on each one) and lightly sprinkle with garlic salt. If the pita bread will not separate, then just cut them into the wedges and brush a small amount of olive oil onto each side instead of using the olive oil spray. Bake at 350 until just starting to brown on edges, about 10 minutes or so.
Peel and seed the cucumber (seed it by cutting lengthwise and running a spoon along the center). Chop finely and layer on top of dip. Follow with diced tomatoes, black olives, pepperoncinis and feta cheese. Top with chopped parsley if desired.