Once your tofu has been well-pressed, you can slice it into thin "finger" shapes, slabs, cubes, or whatever shape you like best.
In a shallow pan or a zip-closing plastic bag, combine the cornstarch, garlic salt, mustard powder and black pepper. Carefully add the tofu, gently tossing to make sure that all sides of the tofu are well coated with the cornstarch mixture.
Heat the oil in a sauté pan or skillet over medium heat, using a non-stick pan if you have it to reduce the amount of oil needed. Add tofu and pan-fry on all sides just until it is just lightly golden brown. Once the tofu has cooked, remove it from the pan and set it aside.
Using the same pan (or a different one, your choice), heat the vegan margarine or butter substitute over very low heat. Once it is melted, add in the wing sauce, stirring just until combined well. Add the cooked tofu, gently turning to coat well on all sides with the wing sauce mixture.
Once that is completely heated, you can take the tofu off of the stovetop heat and serve it while it is warm.
Serve with some vegan ranch dressing if you'd like.