Preheat oven to 375 degrees and prepare a baking sheet with aluminum foil. Rinse chicken breasts and pat dry. Place in a bowl or large re-closable plastic bag. Add 1 Tbsp. of olive oil, ¼, tsp. salt, and 2 tsp. of za'atar spice. Toss to coat evenly and marinate for 10-15 minutes.

Rinse all produce and pat dry. Cut the ends off cucumber, slice in half lengthwise, and remove seeds with a spoon. Cut one half of the cucumber into ½" dice. Grate the other half on a box grater and let drain in a wire mesh strainer. Peel, halve, and slice about ¼ of onion into very thin strips (feel free to use more if you love onion.) Zest and halve lemon. Mince garlic. Stem parsley, reserve a few leaves for garnish and mince the rest. Halve the tomatoes.

In a medium bowl, combine diced cucumber, tomatoes, red onion, lemon zest and juice from half a lemon. Season with a pinch of salt and pepper and mix thoroughly.

Warm a medium pan over medium-high heat, when hot add 1 tsp. of olive oil and marinated chicken. Cook chicken for 5-6 minutes on each side until fully cooked and and a minimum internal temperature of 165 degrees is reached. Rest meat on a cutting board for 5 minutes, then cut into ½" slices.

In a small bowl, combine yogurt, grated cucumber, minced garlic, half of the parsley, and juice of remaining lemon half. Mix thoroughly and season with a pinch of salt and pepper. Brush pita pieces with olive oil and season with remaining za'atar. Place on prepared baking sheet and toast in oven for 5 minutes until warm and pliable. Slice into six even pieces.

Arrange chicken slices and cut pita on the plate. Serve cucumber salad next to the pita. Place a generous dollop of the tzaziki on top of the chicken, or in a small bowl on the side, and garnish with reserved parsley leaves.