For the marinade: In a large resealable plastic bag, combine the grapeseed oil, garlic, onions, oregano and orange juice. Add the steaks and marinate for 24 hours in the refrigerator to flavor and tenderize the meat.
For the chimichurri: In a bowl, combine the garlic, lime zest and juice, cilantro, parsley, oregano, vinegar, chile flakes, olive oil and some salt and pepper. Mix well, then cover and refrigerate overnight to allow the flavors to bloom.
Lightly sprinkle the steaks with salt and pepper and place them on a very hot grill for 3 minutes on each side. Remove the steaks to a plate to rest. Top with butter and lime juice to build flavor.
Plate each steak with 1 cup of the white rice; spoon some chimichurri over the steaks. Serve with the remaining chimichurri on the side.