Marinate the salmon In a 9x13-inch glass dish, whisk the soy sauce, sugar, orange zest, and red pepper flakes. Add the salmon and turn to coat. Cover with plastic and marinate in the refrigerator for 1 hour. Make the relish Using a vegetable peeler, peel the zest from one of the oranges into 1x2-inch strips, avoiding as much of the white pith as possible. Set aside. Cut off enough of the tops and bottoms of the oranges to expose a circle of flesh. Slice off the peel in strips from top to bottom. Working over a medium bowl, cut the segments free from the membranes, letting them fall into the bowl. Cut the grapefruit into segments using the same method. Gently fold the cucumber, mint, ginger, lime zest, sugar, sesame oil, and 1/4 tsp. salt into the citrus. Season to taste with more salt. Smoke the salmon Put the tea, rice, sugar, star anise, cinnamon, and reserved orange zest strips in the center of a sheet of heavy-duty aluminum foil. (If using thinner foil, use 2 or 3 layers.) Fold the foil loosely to form a flat packet. Prepare a medium-high gas or charcoal grill fire. Clean and oil the grill grate; set aside. Set the tea-smoking packet directly on the hot coals or on top of a metal burner shield. Put the grate back on the grill and close the lid. On a charcoal grill, leave the vents partially open and wait for smoke to rise from the vents. On a gas grill, wait 10 minutes, then open the lid to check for smoke. If there is none, close the lid and check again in a few minutes. Drain the salmon and pat dry with paper towels. Brush the salmon lightly with the oil. Arrange the salmon skin side up on the grill grate so that it’s not directly over the packet, and then close the lid. Smoke the salmon, flipping once, until cooked to medium doneness, 3 to 5 minutes per side. Serve with the citrus relish, sprinkled with the scallions and sesame seeds.
