To make this salad, start by preparing the chimichurri. Add the olive oil, cilantro, parsley, minced garlic, lemon juice, oregano, red pepper flakes, salt, and black pepper to a small bowl and mix until everything is fully combined. Taste and adjust the seasoning as needed, then set it aside.
Next, cook the steak. Season both sides generously with salt and pepper. Heat a cast-iron skillet over medium-high heat. Once the pan is very hot — and you'll know it's ready when it just barely starts to smoke — add the steak.
Leave it completely undisturbed for three minutes, then flip it over and cook for another three minutes on the other side.
Remove the steak from the heat and allow it to rest for a full 10 minutes before cutting into it. (This step is important — resting the steak allows the juices to redistribute, so you end up with a perfectly tender, juicy bite every time.) Once it has rested, cut the steak into cubes.
Finally, assemble the salad. Add the chopped Persian cucumbers, halved cherry tomatoes, drained garbanzo beans, thinly sliced red onion, and shaved parmesan to a large bowl.
Pour the chimichurri on top and toss well to coat. Add the cubed steak and toss again. Plate, serve, and enjoy!