In a bowl, mix the cornstarch, brown sugar, smoked paprika, chili powder, onion powder, garlic powder, and kosher salt together. Gently toss the cubed tofu with the spice mixture to coat thoroughly, being careful not to break the tofu cubes. Transfer the coated tofu to a baking sheet and drizzle with a tiny bit of olive oil to prevent sticking. Bake for 30-45 minutes, or until the exterior is lightly golden and dry to the touch, achieving a crispy texture.