Press the firm tofu between paper towels for 15 minutes to remove excess moisture, then cut into 1-inch cubes.
In a medium bowl, toss the tofu cubes with cornstarch, sea salt, and black pepper until evenly coated.
Heat sesame oil in a large non-stick skillet over medium-high heat.
Add the tofu to the skillet and cook for 8-10 minutes, turning occasionally until all sides are golden and crispy.
Remove the tofu from the pan and set aside on a plate.
In the same skillet, add the broccoli florets, sliced red bell pepper, and shelled edamame with two tablespoons of water.
Cover and steam for 3-4 minutes until the broccoli is tender-crisp and bright green.
While the vegetables cook, whisk together the tamari, rice vinegar, minced ginger, and minced garlic in a small bowl.
Return the crispy tofu to the skillet and pour the sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce thickens slightly and coats the ingredients.
Serve immediately topped with toasted sesame seeds and thinly sliced green onions.