1. In a small bowl, whisk together 2 tablespoons olive oil, lemon juice, minced garlic, oregano, salt, and pepper to create the marinade.
2. Place the chicken breasts in a shallow dish or zip-top bag and pour the marinade over them. Let them marinate for at least 30 minutes, or up to 2 hours in the refrigerator for deeper flavor. I often do this step in the morning to save time later.
3. Preheat your grill or grill pan over medium-high heat. Remove chicken from marinade and grill for about 6-7 minutes per side, or until the internal temperature reaches 165°F (75°C) and the chicken is nicely charred.
4. Once cooked, transfer the chicken to a cutting board and let it rest for 5 minutes before slicing it thinly. This step keeps the chicken juicy—something I learned the hard way early on!
5. While the chicken is resting, combine the salad greens, cucumber, cherry tomatoes, olives, and red onion in a large bowl.
6. In a separate small bowl, whisk together the remaining 1 tablespoon olive oil, red wine vinegar, Dijon mustard, a pinch of salt, and pepper to make the dressing.
7. Drizzle the dressing over the salad and toss gently to coat all the veggies.
8. Top the salad with sliced chicken and sprinkle crumbled feta cheese on top.
9. Garnish with fresh parsley or dill if desired, and serve immediately.

A quick tip from my kitchen: always let the chicken rest before slicing. It makes all the difference in tenderness and juiciness, especially when feeding a hungry family. This simple ritual turns a good meal into a great one.