To start, press the tofu block between two towels or two paper towels. Let the tofu sit for 5-10 minutes.
While the tofu is being pressed, mix the cornstarch, salt, & pepper in a small bowl. You can also chop the broccoli at this time if needed.
While the tofu is being pressed, you can also prep the teriyaki sauce. Add the water, soy sauce, brown sugar, mirin, cornstarch, minced garlic, ground ginger, and sesame seeds to a small bowl and mix together until combined. Set aside.
Once the tofu is ready, slice the tofu into triangles. Start by cutting the tofu in half lengthwise, then slice the tofu into 4 evenly sized squares. Finish by cutting each square diagonally to form the triangle shape.
Dip each tofu triangle in the cornstarch mixture until evenly coated and set aside.