1. 1. Marinate the chicken: Cube chicken into 1 inch pieces. In a bowl or zip top bag, combine olive oil, lemon juice, red wine vinegar, minced garlic, oregano, thyme, salt, and pepper. Add chicken and toss to coat. Refrigerate for at least 30 minutes, up to 4 hours.

2. 2. Cook the chicken: Heat a large skillet over medium high heat. Add chicken in a single layer (cook in batches if needed). Cook for 5-7 minutes, flipping halfway, until golden brown and internal temperature reaches 165°F. Set aside to cool.

3. 3. Prepare the grains: Cook brown rice or quinoa according to package directions. Fluff with a fork and cool completely.

4. 4. Chop the vegetables: Halve cherry tomatoes, dice cucumber, thinly slice red onion, and pit and halve olives. Ensure vegetables are dry.

5. 5. Make the tzatziki dressing: In a small bowl, combine Greek yogurt, grated and squeezed cucumber, minced garlic, lemon juice, fresh dill, salt, and pepper. Stir well.

6. 6. Assemble the bowls: Divide cooled grains among 4 containers. Top with chicken, cherry tomatoes, cucumber, red onion, olives, and feta if using. Store tzatziki separately. Garnish with fresh dill or parsley if desired. Secure lids and refrigerate.