Take steak out of fridge and coat with 1 tablespoon of the salt. Set on a rack set inside a sheet pan and let rest at room temperature for 30 minutes. The internal temperature of the steak should come up to somewhere between 45 and 50ºF. In the meantime, get out a large piece of heavy-duty aluminum foil (about 16-by-18 inches) and place it near the stove.
About 5 minutes before the raw steak has finished resting at room temperature, place a 12-inch cast-iron skillet over the highest heat you've got for a full 5 minutes. If you've got an infrared thermometer, check that the skillet has reached at least 550ºF at the hottest point. It will already be smoking at this point, so either crank your hood or open a window or both. If there's isn't smoke, you ain't doin' it right.
Evenly sprinkle the remaining tablespoon of salt across the pan. Coat the steak with the canola oil, then transfer it to the middle of the pan. Do not interrupt the steak for 2 minutes. Flip the steak, rotating it perpendicularly to where it initially went down into the skillet (it‚Äôll hit additional salt this way) and cook for another 2 minutes, uninterrupted.
Turn the steak up on one long edge and cook 30 seconds. Turn the steak onto the opposite long edge and cook another 30 seconds. If you‚Äôre checking, its internal temperature should be between 70 and 72ºF.
Transfer the steak to the foil and wrap it tightly. Let it rest for 3 minutes. Leave the heat on under the skillet; it‚Äôll continue to smoke and should jump up even hotter, to around 700ºF in its hottest spots.
After 3 minutes, unwrap the steak and place it back in the pan for 3 minutes, then flip and cook for another 3 minutes, continuing to rotate the steak around the pan as you flip it to pick up the salt.
Flip and cook for 2 minutes, then flip and cook for a final 2 minutes. The steak should be at around 120ºF; these cooking times will give you a perfect medium-rare steak. If you like your steak more on the rare side, decrease the cooking times to 2 minutes, 2 minutes, 1 minute, and 1 minute.
Return the steak to the foil, wrap tightly, and let rest for 5 more minutes to bring the heat up to 130ºF. Unwrap, slice on the bias, and serve with the sauce remaining in the foil.