2 tbsp. sugar
1 tsp. kosher salt
6 (6-8 oz.) skin-on salmon fillets
2 c. wood chips, half of chips soaked in water for 15 minutes and drained
Combine sugar and salt in bowl. Set salmon on wire rack set in rimmed baking sheet and sprinkle flesh side evenly with sugar mixture. Refrigerate, uncovered, for 1 hour. With paper towels, brush any excess salt and sugar from salmon and blot dry. Return fish on wire rack to refrigerator, uncovered, while preparing grill.
Place all chips in smoker box, directly over center burner. Turn center burner to high (leave other burners off), cover, and heat grill until hot and wood chips begin to smoke, 15 to 25 minutes. Turn center burner to medium. (Adjust as needed to maintain grill temperature of 275 to 300 degrees.)
Clean and oil cooking grate. Fold piece of heavy-duty foil into 18 by 6-inch rectangle. Place foil rectangle over cool side of grill and place salmon pieces on foil, spaced at least 1/2 inch apart. Cover grill and cook until center of thickest part of fillet registers 125 degrees and is still translucent when cut into with paring knife, 30 to 40 minutes. Transfer to platter and serve, or allow to cool to room temperature.