In small bowl mix chili powder, cumin, brown sugar, 1/4 teaspoon salt, and 1/8 teaspoon black pepper. Rub spice mixture on salmon. Brush cabbage wedges with 1 tablespoon of the oil.
On charcoal grill, place salmon and cabbage on greased rack of uncovered grill, directly over medium coals. Grill salmon 4 to 6 minutes for each half-inch of thickness or until it flakes when tested with a fork, turning once halfway through cooking time. Grill cabbage 6 to 8 minutes, turning once.
Meanwhile, peel carrot and cut in wide strips. Remove fish and cabbage from grill. Coarsely cut cabbage; combine with carrot and 1 to 2 tablespoons remaining oil. Season with salt and pepper. Serve with oranges. Makes 4 servings.