Season steak with Kosher salt and pepper. Heat oil in a cast-iron skillet over medium-high heat, 1 turn of the pan. Add crushed garlic and stir 30 seconds to flavor the oil; remove. Add the steak and cook, turning occasionally, about 7-8 minutes for pink centers; remove to a plate. Cook cut lemon, flesh-side down, to caramelize it. Let steak rest then douse with juice of 1/2 lemon.
Dress baby kale and or baby arugula with juice from remaining lemon half, EVOO, salt and pepper. Add big curls of Parmigiano-Reggiano shaved with a vegetable peeler.
Serve sliced steak alongside salad plain or with your choice of optional additions.