Stir the hot sauce and cornstarch together in a small container. Stir until the cornstarch is fully dissolved, then stir in the vegan butter.
Coat the bottom of a large skillet with the oil and place it over medium heat.
Give the oil a minute to heat up, then add the tofu cubes in an even layer. Cook the tofu for about 10 minutes, flipping the pieces once or twice until they're browned on multiple sides. Sprinkle them with a pinch of salt while they cook.
Carefully pour the sauce into the skillet with the tofu. Stir everything up and simmer the tofu in the sauce for 1 to 2 minutes, until the sauce thickens slightly.
Remove the skillet from heat and let the tofu cool for a few minutes.
Transfer the tofu to a medium mixing bowl and add the carrot, celery and scallions. Stir everything until combined.
Serve with accompaniments of choice.
Serve over salad greens, in tortillas, or in sandwiches with vegan ranch dressing or vegan blue cheese.