Lamb Burger with Chunky Mint Tzatziki

1 Preheat the oven to 350°F. Combine yogurt, cucumber, mint, 3 tablespoons chives, 1 tablespoon chopped oregano, 1 teaspoon garlic, and lemon juice in a small bowl. Season to taste with salt and pepper. 2 In a large bowl, gently combine the lamb, remaining 2 teaspoons garlic,remaining chives, remaining oregano leaves, and 1/2 teaspoon pepper. Form the mixture into two burgers, and drizzle on both sides with olive oil. Season liberally with salt. Preheat a coal or gas grill to high heat. Alternatively, rub a grill pan with olive oil and preheat over medium-high heat until lightly smoking. Grill burgers, turning occasionally, until an instant read thermometer inserted into the center registers 125 to 130°F for medium rare, or 135 to 140°F for medium, 5 to 9 minutes. Transfer to a large plate and tent with foil for 3 minutes 3 Stuff burgers in pita and serve with tzatziki.