Make the Tzatziki Dressing: In a medium bowl, combine the Greek yogurt, grated cucumber, pressed garlic, olive oil, and fresh dill. Season with salt and pepper to taste. Mix until well combined and creamy. Set aside.

Prepare the Salad Ingredients: In a spacious mixing bowl, combine the diced cooked chicken, chopped romaine lettuce, halved grape tomatoes, pepperoncini, Kalamata olives, and diced red onion.

Assemble the Salad: Drizzle the prepared tzatziki dressing over the salad mixture. Toss delicately to ensure all the ingredients are evenly coated with the dressing.

Serve: Scoop the salad into a serving bowl or divide it among individual plates. Enjoy it on its own, or pair it with pita bread or serve it over a bed of rice for a heartier meal.