Combine first 9 ingredients in a slow cooker (chicken through pepper) or combine in a resealable bag to use as a freezer meal. Stir well. Cook on low 6 hours or on high 4 hours if cooking from fresh. If cooking from freezer, put frozen block in crockpot and cook for 6 hours on high or 8 hours on low. Shred chicken. Serve in warmed pitas, topped with Tzatziki, cucumbers, and tomatoes
*Homemade Greek Pitas:
Place liquid ingredients in bowl of a stand mixer. Add flour. Add salt to the side of the bowl. Make a well in the center of the flour, and add yeast to the well. Fit mixer with a dough hook. Stir on low speed 5 minutes or until dough ball forms and cleans the sides of the bowl. Dough should be soft and springy and slightly sticky. Spray dough ball with cooking spray. Turn to coat all sides. Cover loosely with plastic wrap, and allow to rise 1 hour in a warm, draft-free place.
When dough has doubled in bulk, punch it down by hand. Divide into 8 equal portions. Form each portion into a ball. Roll each ball into an 1/8 inch thick circle (about).
Preheat griddle to 350. Cook each circle 2 minutes, or until bubbly and puffy. Flip over, and cook 2 minutes longer. Set aside and keep warm.
* You can either make your own pitas or buy them. So omit the ingredients for the homemade pitas if you end up buying them.
* * Homemade Tzatziki Sauce: check out this recipe here , if you would prefer to make your own sauce.