Pound the steak on both sides with a meat tenderizer or pierce with a fork. Transfer to a large resealable plastic bag; add 2 tablespoons olive oil, the lemon juice, 1/2 teaspoon salt and a few grinds of pepper. Seal the bag and shake to coat; marinate in the refrigerator, 2 to 8 hours.
Meanwhile, make the pesto: Toast the pine nuts in a small skillet over medium-high heat, tossing occasionally, until slightly golden, about 3 minutes; let cool. Pulse the parsley, garlic and red pepper flakes in a food processor until almost smooth. Add the toasted pine nuts, cheese and 5 tablespoons olive oil and pulse until combined. Transfer to a bowl and stir in 3 tablespoons water and the olives; season with salt.
Remove the steak from the marinade and pat dry. Bring to room temperature, about 30 minutes.
Heat a large cast-iron or other heavy skillet over medium-high heat; add the remaining 1 tablespoon olive oil, then add the steak and cook until a dark crust forms, about 7 minutes. Turn and cook until a thermometer inserted into the center of the steak (from the side) registers 130 degrees F for medium rare, about 8 more minutes. Transfer to a cutting board and let rest 10 minutes.
Brush the steak with some of the pesto. Thinly slice against the grain and serve with the remaining pesto.