In a small bowl, mix all the spices until well blended.
Brush salmon with melted butter. Rub spices over salmon. Set aside.
Heat a large cast-iron skillet on high heat. When hot, add salmon, skin side down. Let cook for 2 to 3 minutes. Allow skin to get crispy. Flip and cook for another 2 to 3 minutes. Remove to plate. Let sit for a few minutes before serving.