How to Make It
Stir together brown sugar, salt, chile powder, garlic powder, oregano, cumin, cayenne, and black pepper in a medium bowl. Transfer 1/4 cup spice mixture to a small bowl, and whisk in pineapple juice. Cover with plastic wrap, and place in refrigerator until ready to use. Set aside remaining spice mixture.
Line a 13- x 9-inch glass or ceramic baking dish with a large sheet of plastic wrap, leaving a 12-inch overhang on 2 long sides. Spread reserved spice mixture on plastic wrap in an even layer slightly larger than the salmon. Place salmon, skin side up, on spice mixture. Wrap plastic wrap tightly around salmon; cover baking dish with plastic wrap, and refrigerate until fish is barely firm to the touch, 10 to 12 hours.
Unwrap salmon, and discard plastic wrap. Rinse off most of spice mixture, and pat salmon dry. Lightly grease a flame-proof rack or perforated grill pan set over a large baking sheet with cooking spray; add salmon, skin side down. Brush salmon with 2 tablespoons pineapple juice mixture; refrigerate, uncovered, until surface of salmon forms a pellicle (a thin, slightly dry layer), about 4 hours.
During the last hour of chilling the salmon, soak wood chips in water; drain. Using lump charcoal, prepare a fire in a smoker according to manufacturer’s instructions. (If necessary, follow instructions for indirect heat.) Place 1 cup soaked wood chips on hot coals. Maintain internal temperature of 150°F to 170°F for 15 to 20 minutes. Place rack or perforated grill pan with salmon on smoker. Brush salmon with 2 tablespoons pineapple juice mixture. Close lid; smoke salmon until an instant-read thermometer inserted in thickest portion registers 145°F, about 2 hours, adding small handfuls of wood chips to coals and brushing salmon with remaining pineapple juice mixture every 30 minutes.
Remove salmon from smoker and let cool completely on rack, about 1 hour. Using a fish spatula, carefully remove salmon from rack, and wrap tightly in plastic wrap. Refrigerate until chilled, about 2 hours or up to overnight. To serve, cut salmon into thick slices or flake into large pieces.