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.
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.
Heat 1 tablespoon canola oil in a large nonstick skillet over medium-high heat.
Add tofu to pan; saut 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; saut 30 seconds.
Add garlic to pan; saut 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.