• In a large bowl, combine the garlic, lemon juice, red wine vinegar, olive oil, yogurt, oregano, salt and pepper in a medium bowl and whisk well. Add the chicken pieces to the bowl and mix well to coat. Cover bowl or move into ziploc bag and refrigerate for about 1 hour.

To make the tzatziki sauce:

• While the chicken is marinating, shred the cucumber or chop in food processor. Toss with 1/2 teaspoon salt and set over a strainer or paper towels (a coffee filter also works well) and let sit for 20 to 30 minutes. Squeeze cucumber to remove as much liquid as possible.
• In a medium bowl, combine yogurt, cucumber, lemon juice, dill, garlic, and white wine vinegar. Season to taste with salt and pepper. Drizzle lightly with olive oil. Refrigerate for at least 30 minutes.

To cook the chicken on the grill:

• Preheat over medium-high heat. Grill the chicken, turning occasionally until the internal temperature reaches 165 degrees on a thermometer, about 10 to 15 minutes. Remove from grill and let rest for 5 minutes. Slice or chop into pieces.
• Serve on pita bread with feta cheese, tomatoes, red onion, and tzatziki sauce.

To cook the chicken in the oven:

• Preheat oven to 400 degrees. Coat a baking dish with oil or nonstick spray and arrange chicken in a single layer. Cover with parchment paper, tucking the paper around the chicken so it is completely covered. 
• Bake for 30 to 40 minutes, until the chicken reaches 165 degrees when tested with an internal thermometer. Remove from oven and let rest for 5 minutes. Slice or chop into pieces.
• Serve on pita bread with feta cheese, tomatoes, red onion, and tzatziki sauce.