Add garlic, cucumber, and dill to a food processor and chop ingredients. Add yogurt, sour cream, lemon juice, and dill, and pulse to blend. Add salt to taste. Refrigerate for one hour.

Preheat oven to 450 degrees F.

Place pita breads domed side down on a baking sheet covered with parchment paper. Slather each bread with 1-2 tablespoons of tzatziki, then top each with about ⅓ to ½ cup mozzarella cheese.

Layer chicken breast, olives, tomatoes, and artichoke hearts on top of the mozzarella, then sprinkle with feta cheese and oregano.

Place in the oven and bake for 10-12 minutes or until cheese is melted and feta cheese starts to turn golden. Remove, garnish with fresh dill sprigs, red chili flakes, and more feta if desired, cut into quarters and serve.