Preheat oven to 400°F. Line a baking sheet with parchment paper.
Remove tofu from packaging and drain. Wrap in a clean towel and press firmly to remove excess moisture.
Cut tofu into 1-inch cubes and place in a mixing bowl.
Toss with tamari first, then cornstarch, then breadcrumbs until evenly coated.
Spread tofu in a single layer on the prepared baking sheet. Make sure pieces are not touching.
Bake for 25 minutes. Turn off oven and let tofu rest inside for another 5 minutes.
While tofu bakes, whisk together all sauce ingredients except the cornstarch and water in a small saucepan.
Mix cornstarch and water together in a small bowl, then whisk into the sauce.
Heat sauce over low-medium heat, whisking, until it bubbles and thickens. Remove from heat.
Let tofu cool 5 minutes, then transfer to a bowl. Toss with half the sauce. Reserve the rest for serving.
Serve over rice with your favorite toppings and a drizzle of extra sauce.