Preheat grill to medium-high heat.
Drizzle the sardines with olive oil and lemon juice. Sprinkle with oregano, salt, and pepper.
Grill the sardines for about 3-4 minutes on each side, until they are cooked through and charred.
In a large bowl, combine the salad greens, cherry tomatoes, olives, red onion, feta cheese, and parsley.
Remove the sardines from the grill and let them cool slightly. Flake the sardines into bite-sized pieces and add them to the salad.
Toss the salad gently to combine all the ingredients.
Serve the Mediterranean grilled sardine salad immediately and enjoy!