In a large mixing bowl, combine the ground chicken, minced garlic, grated onion, chopped parsley, mint, dried oregano, crumbled feta, breadcrumbs, and a generous pinch of salt and pepper. Use your hands to gently mix until all the ingredients are evenly distributed, then shape into four patties.

Heat a skillet over medium heat and add olive oil. Once shimmering, place the patties in the skillet and cook for 5–6 minutes per side until golden brown and juices run clear.

In a medium bowl, mix Greek yogurt, grated cucumber, minced garlic, lemon juice, dill, and a pinch of salt and pepper until smooth.

Toast the burger buns in the skillet or a toaster until golden brown.

Spread tzatziki on the bottom half of each bun, layer with lettuce, place a patty, and top with a slice of tomato and the top bun.