Spray a crockpot with cooking spray. Add the onions and garlic.

In a small bowl combine the oregano, dill, paprika, cayenne, crushed red pepper, salt and pepper. Sprinkle the pork with half of the spice mixture.

Heat a large skillet over medium-high heat and add a drizzle of olive oil. Once hot, add the pork and sear on all sides until golden brown (about 2 minutes per side). Try and get a really good caramelization on the meat.

Add pork to the prepared crockpot and sprinkle with the remaining seasonings and any drippings from the pan. To the crockpot add the 1/3 cup olive oil, lemon juice, red wine vinegar, greek yogurt and 3/4 cup of water. Cover and cook on low, 8 hours. or high for 4-6 hours. If possible check the pork a few times during cooking. If needed add some water to keep the meat moist.

To prepare the tzatziki pour any liquid off the surface of the greek yogurt. (I find it is best to use full fat greek yogurt for this, but 2% works ok as well. You want the yogurt to be thick, so if your greek yogurt seems thin strain it through a fine mesh strainer). Mix together the greek yogurt, diced cucumber, garlic, white wine vinegar, dill, oregano, salt and pepper to taste, and lemon juice. Drizzle with olive oil. Refrigerate for at least 30 minutes before serving to allow the flavors to meld.

If making the tapenade, dice the olives and mix in a small bowl with the garlic, pepperoncini and parsley. Set aside in the fridge until read to serve.

After 8 hours (or 4-6 on high) remove the pork and set aside to cool slightly. Once cool enough to touch shred the pork with two forks, it should fall apart easily. Return the pork to the crockpot and toss with the onions. Crank the heat to high. Allow the pork to get warm for five minutes.

Heat pitas (I just popped them in the microwave for a few seconds). Top with chicken, tzatziki sauce, sliced tomatoes, red onion, feta cheese and tapenade if using. Serve immediately.