1. Combine vinegar, mirin, soy sauce, sesame oil, 1/8 teaspoon salt, and 1/8 teaspoon red pepper in a medium bowl; stir with a whisk.
2. Cut tofu crosswise into 8 (1/2-inch-thick) slices. Arrange tofu on several layers of paper towels. Top with several more layers of paper towels; top with a cast-iron skillet or other heavy pan. Let stand 30 minutes. Remove tofu from paper towels. Cut tofu into (1-inch) cubes. Sprinkle tofu with remaining 1/8 teaspoon red pepper.
3. Heat 1 tablespoon canola oil in a large nonstick skillet over medium-high heat. Add tofu to pan; sauté 8 minutes or until crisp, carefully turning to brown on all sides. Remove tofu from pan; keep warm. Heat remaining 1 tablespoon canola oil in pan. Add ginger and green onions to pan; sauté 30 seconds. Add garlic to pan; sauté 30 seconds or just until golden. Add ginger mixture to vinegar mixture; stir well. Pour vinegar mixture over tofu; sprinkle evenly with 1/4 teaspoon salt and sesame seeds.