In a large bowl, add steak, sea salt and freshly ground pepper to taste, oregano, 2 tablespoons olive oil and garlic. Stir to combine and marinate in the refrigerator for 20 minutes.
On an indoor grill over medium heat, grill steak 4 to 5 minutes each side until cooked through.
In a large bowl, add tomatoes, onion, cucumber, olives, capers, feta, red wine vinegar, basil and remaining olive oil. Stir to combine.
Slice steak and serve with salsa.