Preparation Mix soy sauce, wasabi powder and garlic powder in 8x8x2-inch glass dish. Add tuna; turn several times to coat with marinade. Let stand 15 minutes. Meanwhile, cook beans in large pot of boiling salted water until crisp-tender, about 4 minutes. Drain well. Heat sesame oil in heavy large skillet over medium-high heat. Remove tuna from marinade; reserve marinade. Sprinkle tuna on all sides with pepper. Add tuna to skillet and cook until just opaque in center, about 3 minutes per side. Transfer tuna to plates. Add green beans, sugar and reserved marinade to skillet. Cook until sauce is reduced enough to coat beans, stirring occasionally, about 4 minutes. Using tongs, place beans alongside tuna and serve.
Preparation Mix soy sauce, wasabi powder and garlic powder in 8x8x2-inch glass dish. Add tuna; turn several times to coat with marinade. Let stand 15 minutes. Meanwhile, cook beans in large pot of boiling salted water until crisp-tender, about 4 minutes. Drain well. Heat sesame oil in heavy large skillet over medium-high heat. Remove tuna from marinade; reserve marinade. Sprinkle tuna on all sides with pepper. Add tuna to skillet and cook until just opaque in center, about 3 minutes per side. Transfer tuna to plates. Add green beans, sugar and reserved marinade to skillet. Cook until sauce is reduced enough to coat beans, stirring occasionally, about 4 minutes. Using tongs, place beans alongside tuna and serve.