Marinated chicken, cool tzatziki, maybe some pita on the side. This Greek classic is a high protein chicken dinner that tastes like a Mediterranean vacation.
Trim and cut the chicken breast into 1-inch cubes, then set aside in a large bowl.
In a separate bowl, combine olive oil, juice and zest from the lemon, minced garlic, dried oregano, salt, and black pepper. Pour this marinade over the chicken and toss thoroughly. Cover and refrigerate for at least 30 minutes (up to 2 hours) for more flavor.
For the tzatziki, grate the cucumber and squeeze out excess moisture. Mix with Greek yogurt, minced garlic, lemon juice, and chopped fresh dill. Season with salt and pepper, then chill.
Thread marinated chicken pieces onto skewers. Preheat grill or grill pan to medium-high heat. Grill chicken skewers for 4–5 minutes per side, turning once, until they have clear grill marks and reach 165°F internal temperature.
Warm pita bread slices briefly on the grill. Serve chicken skewers on a plate with a generous spoonful of tzatziki, sliced red onion, and pita bread on the side.