While it's not absolutely essential, but I do find this to make a big difference in the texture of the tofu. That said, if you are short on time, you can just pat the tofu dry with some paper towels to get some of the external water off. Since my recipe uses extra-firm tofu, it naturally won’t have quite as much moisture in it. While unpressed tofu won’t absorb as much flavor, the end result will still be good! You’ll have vegetarian kung pao tofu that is satisfying and tasty!