Bring steak to room temperature 30 minutes prior to grilling. Preheat an indoor grill to medium heat and lightly oil the grate.
Brush steak with olive oil and season with salt and pepper. Grill until slightly charred, firm, and reddish-pink and juicy in the center, about 11 minutes per side. Hold steak with tongs to sear edges. An instant-read thermometer inserted into the center should read 130 degrees F (54 degrees C). Transfer steak to a cutting board; cover loosely with aluminum foil, and let rest for 10 minutes.
Meanwhile, pulse shallot, garlic, parsley, oregano, red pepper flakes, kosher salt and pepper together in a food processor until roughly chopped. Add red wine vinegar, olive oil, and water; pulse to a textured sauce. Transfer to a serving bowl.
Slice steak and serve with prepared chimichurri sauce.
