In a small bowl, combine all your dry ingredients for the salmon and generously cover each salmon fillet with the spice rub on the flesh side only.
Heat oil in a large cast-iron over medium heat.
When the oil is hot, add the salmon flesh side down. Cook for about 3 minutes then flip over and cook another 3 minutes until skin is crispy and the salmon flakes easily with a fork.
Transfer the cooked salmon to a plate and use a fork to break the salmon into large chunks.
Char the tortillas on a gas stovetop or grill, then fill each tortilla with salmon, lettuce, red onion, cilantro, and guacamole.