Slice the tofu into 6 slabs crosswise and blot well on paper towels or clean tea towels (or use a handy tofu pressing device). Place it in a mixing bowl, and mash well with a large fork or potato masher. Or, just crumble with clean hands.
Add the diced celery and scallion to the tofu
In a small bowl, combine the mayonnaise, mustard, curry powder, and optional nutritional yeast and mix well. Pour the mayonnaise mixture over the tofu mixture, and stir well to combine.
Add more vegan mayonnaise if you'd like a creamier consistency. Season to taste with salt and pepper, and add more curry, if you'd like. Serve as suggested, below.