Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Press the tofu for at least 15 minutes using a tofu press or heavy skillet 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 every piece is evenly coated.
Spread the tofu in a single layer on the prepared baking sheet and bake for 25-30 minutes, flipping halfway through, until the edges are golden and crispy.
While the tofu is in the oven, whisk together the peanut butter, tamari, rice vinegar, and sriracha in a small bowl until the sauce is smooth and emulsified.
Place the broccoli florets and shelled edamame in a steamer basket over boiling water and steam for 5-7 minutes until they are tender-crisp and bright green.
Remove the crispy tofu from the oven, toss it immediately in the peanut sauce to coat, and serve over the steamed vegetables garnished with sesame seeds.