Drain the extra firm tofu and press it between paper towels for at least 15 minutes to remove excess moisture.
Cut the pressed tofu into 1-inch cubes and toss them in a bowl with cornstarch until evenly coated.
In a small jar, whisk together the tamari, rice vinegar, grated ginger, and minced garlic to create the stir-fry sauce.
Heat a large non-stick skillet over medium-high heat and add the toasted sesame oil.
Add the tofu cubes to the skillet in a single layer and sear until golden brown and crispy on all sides, then remove and set aside.
In the same skillet, add the broccoli florets, sliced bell pepper, and edamame, sautéing for 4-5 minutes until tender-crisp.
Return the crispy tofu to the pan, pour the sauce over the mixture, and toss for 1 minute until the sauce thickens and coats everything.
Garnish with sesame seeds and red pepper flakes before serving.