Start by rinsing your salmon filets. Pat dry with a paper towel, and sprinkle the salmon on both sides with salt.
Preheat a skillet over medium-high heat. A standard 10-inch to 12-inch skillet can fit 4 salmon filets comfortably, depending on how large they are. You want about an inch (2.5cm) of space between them so they don’t steam. If using a stainless steel, carbon steel, or cast iron skillet, heat until a splash of water beads and jumps around the pan. If it’s smoking vigorously, it is too hot. If using a nonstick skillet, simply heat until the oil shimmers in the pan.
Swirl the oil in the pan, and place the salmon filets skin-side down, about 1 inch apart. Cook for 4 minutes on the first side, without moving the fish. Flip, using another spatula to hold the uncooked side steady if needed. Reduce the heat to medium and rotate the pan 180°. Cook on the second side for another 4-5 minutes.