Stir together the soy sauce, sherry, cornstarch, sugar, and pepper in a medium bowl. Add the pork, then set it aside to marinate for 30 minutes.
Lightly beat the eggs with the salt. Warm the sesame oil in a large nonstick skillet over medium heat. Scramble the eggs until soft-cooked, about 1 minute, then transfer them to a large plate and break them into small pieces. Wipe the pan clean.
Heat 1 teaspoon of the canola oil in the same skillet over medium-high heat. Remove the pork from the bowl, gently squeezing the strips to reserve the excess marinade. Add the pork to the pan in a single layer, let it cook undisturbed for 2 minutes, then stir-fry it until it is caramelized and just cooked through, about 2 minutes more. Transfer it to the plate with the scrambled eggs.
Add another 2 teaspoons of the canola oil to the skillet and stir-fry the mushrooms, about 2 minutes. Add the cabbage and carrots and stir-fry until all the vegetables are just tender, about 3 minutes. Make a well in the center of the vegetables and add the remaining teaspoon of canola oil. Add roughly half the scallions, the ginger, and the garlic, and stir-fry them for 1 minute, then combine them with the other vegetables. Create a well again in the center of the mixture, add the reserved marinade, and allow it to simmer for 2 minutes. Return the pork and egg to the skillet and toss the mixture until it is heated through, about 2 minutes. Transfer it to a serving bowl.
Warm the tortillas under a damp paper towel in the microwave, about 50 seconds. To serve, place each tortilla on a plate, smear it with a teaspoon of hoisin sauce, and add the pork mixture. Sprinkle on some of the remaining scallions, then roll up the tortilla.