Marinate the Chicken:
In a mixing bowl, whisk together olive oil, lemon juice, lemon zest, garlic, oregano, paprika, salt, and pepper. Add the chicken breasts, coating them thoroughly. Cover and refrigerate for at least 30 minutes or up to 2 hours.
Grill the Chicken:
Preheat your grill or grill pan over medium-high heat. Remove the chicken from the marinade and grill for 6–8 minutes per side, or until the internal temperature reaches 165°F (75°C). Remove from the grill and let the chicken rest for 5 minutes before slicing.
Prepare the Dressing:
In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, garlic, salt, and pepper until well combined.
Assemble the Salad:
In a large salad bowl, layer the mixed greens, cherry tomatoes, cucumber, red onion, olives, and feta cheese. Top with the sliced grilled chicken.
Drizzle & Serve:
Drizzle the dressing over the salad just before serving. Toss gently to combine, and garnish with fresh parsley or dill if desired.