Pat salmon dry. In a small bowl, add salt, black pepper, chili powder, ancho chili powder, garlic powder, and onion powder. Stir together to combine.
Season the flesh side of the salmon only with the seasoning mixture.
Heat olive oil in a large nonstick skillet over medium-heat, heat oil. Add the salmon skin side down. Cook until the skin is crispy and browned, about 4 to 5 minutes, then flip and cook for another 3 to 4 minutes depending on the thickness, until the flesh is opaque and flaky.
Transfer salmon to a plate and let it rest and cool slightly for 3 minutes. Flake the salmon into large pieces using a fork, discarding the skin if desired.
Serve in warm corn or flour tortillas with fish taco slaw and garnish with chopped cilantro, sliced radishes, and lime wedges.