Wrap the filets completely in paper towels while you heat a large cast iron skillet (a heavy stainless steel pan will do in a pinch but I'd avoid non-stick for this), over medium heat for 5 minutes.
When the skillet is hot, season the filets with the salt. Add the oil to the skillet and carefully tilt to evenly cover the bottom. When the oil shimmers, slide the filets in, skin-side down, pressing each filet firmly down with a flexible spatula or fish turner to ensure contact.
Reduce the pan heat to medium-low and cook for 3 minutes, then cover the skillet and cook another 2 minutes.
Carefully flip the filets, replace the cover and cook for another minute, or until done to your liking (I like mine at an internal temp of 130F).
To serve, slice each filet in half, place atop the kale & quinoa and enjoy.