In a large platter or bowl, whisk together the olive oil, lemon juice, garlic, and oregano.
Using a meat mallet, tenderize the steak by pounding 15-20 times on each side all over. (this is not necessary, but helps create a more tender steak and helps the marinade better seep into the meat).
Place the tenderized steaks into the marinade and flip back and forth in the marinade to evenly coat. Then, season both sides of the meat with the kosher salt and pepper. Cover and let marinade for at a minimum 20- 30 minutes at room temperature, or for 4 to 6 hours in the fridge.
Heat grill over medium-high heat (375- 400 degrees F) and oil the grill grates (to do this, dip a wadded paper towel in a little oil and, using tongs, wipe the oil evenly over the grate. Be careful not to use too much oil, because that's a sure fire way to start a good flare-up—a little goes a long way here.)
Carefully place the steaks on the hot grill and cook until the pieces turn golden and grill marks appear, about 5 minutes per side. The lid should be closed throughout the cooking process. Add the last few minutes of the cooking time, place the lemons, flesh side down, until it softens and grill marks appear, 2 to 3 minutes.
Remove from the grill and let rest for 10 minutes before slicing and serving. Squeeze lemon over the top and enjoy!