Press the extra firm tofu for 15 minutes to remove excess moisture, then cut into 1-inch cubes.
Toss the tofu cubes in a large bowl with cornstarch, sea salt, and black pepper until each piece is evenly coated.
Heat the toasted sesame oil in a large non-stick skillet over medium-high heat until shimmering.
Add the tofu to the skillet and sear until golden and crispy on all sides, which takes about 8 to 10 minutes.
Remove the crispy tofu from the pan and set it aside on a plate.
In the same pan, add the broccoli florets, sliced red bell pepper, and edamame with a splash of water, covering for 2 minutes to steam-soften.
Stir in the minced garlic and grated fresh ginger, sautéing for about 1 minute until the aromatics are fragrant.
Return the crispy tofu to the pan and drizzle the tamari over the mixture.
Toss everything together for 1 to 2 minutes until the sauce thickens slightly and coats the tofu and vegetables.
Garnish the stir-fry with sesame seeds and serve immediately while hot.