Rinse fish; pat dry. In small bowl combine soy sauce, wasabi powder,1/2 teaspoon of the sesame oil, and 1/4 teaspoon of the sugar. Brush soy mixture over fish. Grill fish on the lightly greased rack of an uncovered grill directly over medium heat for 6 to 9 minutes or until fish flakes easily when tested with a fork, turning after 4 minutes.
Meanwhile, for vegetable slaw, in medium bowl combine the zucchini, radishes, pea pods, and 2 tablespoons of the chives. Stir together the remaining sesame oil, remaining sugar, and vinegar. Drizzle over the zucchini mixture; toss to combine. Sprinkle remaining chives over fish. Serve fish with vegetable slaw. Make 4 servings.