Pat salmon fillets completely dry with paper towel. This is the key step for a good crust.
Mix all spice rub ingredients together in a small bowl. Press the rub firmly onto the flesh side (and skin side if desired) of each fillet.
Heat oil in a skillet over medium-high heat until shimmering.
Place salmon skin-side down. Press gently with a spatula for the first 30 seconds to prevent curling. Cook for 5–6 minutes without moving, until the flesh turns opaque about two-thirds of the way up the sides.
Flip and cook for 1–2 minutes more. Remove from heat while the very centre still looks slightly underdone.
Rest for 1–2 minutes before serving.
Notes
Salmon is done when it flakes easily with a fork and reaches an internal temperature of 63°C (145°F). For a milder heat, reduce or omit the chili powder.