In a 12-inch cast iron skillet preheat oil over medium heat. Season skirt steak with salt and pepper. Cook steak on each side for 3-4 minutes for medium-rare.
Add chopped parsley, oregano, garlic, and red wine vinegar to food processor. Process until smooth. Pour into a bowl. Add red pepper flakes, salt, pepper, and olive oil and stir until incorporated. Let sit for 20 minutes.