Preheat the grill or saute pan over medium-high heat.
Season the chicken breasts with dried oregano, salt, and pepper.
Grill the chicken for about 6-7 minutes per side or until cooked through and no longer pink in the center. Cooking time may vary based on the thickness of the chicken breasts. Once cooked, set aside to rest for a few minutes before slicing.
While the chicken is cooking, prepare the lemon-oregano dressing. In a small bowl, whisk together the extra-virgin olive oil, fresh lemon juice, dried oregano, minced garlic, salt, and pepper. Set aside.
In a large salad bowl, combine the mixed salad greens, cherry tomatoes, diced cucumber, sliced red onion, Kalamata olives, and crumbled feta cheese.
Slice the grilled chicken breasts into thin strips.
Add the sliced chicken to the salad bowl. Drizzle the lemon-oregano dressing over the salad.
Toss the salad gently to coat all the ingredients with the dressing.
Sprinkle chopped fresh parsley over the top of the salad for an extra burst of flavor and color.
Serve the Mediterranean Chicken Salad immediately as a light and satisfying meal.