Wrap the tortillas in aluminum foil and heat in a 300°F oven (or toaster oven) while you cook the stir fry. Alternatively, you can heat the tortillas individually in a hot, dry skillet, or microwave them in a stack for 1 minute (make sure to do this just before you're ready to serve dinner).
Add 1/4 cup dried wood ear mushrooms to a small bowl. Cover with cold water by at least 1 inch. Let the mushrooms sit in the water for at least 15 minutes to rehydrate while you start prepping the other ingredients.
Cut the pork tenderloin in half lengthwise, then thinly slice both halves of the tenderloin. (Note that this is easiest to do if the tenderloin is partially frozen.) Toss the sliced pork with 1 Tablespoon cornstarch, 1 teaspoon water, 1/2 teasoon kosher salt, and 1/4 teaspoon white pepper in a small bowl. Set aside while you prep the vegetables.
Peel 2 medium carrots and Julienne them or cut them into matchsticks (note that using a mandoline will make this job go a little faster.) Add them to a large bowl.
Thinly slice 2 medium stalks celery on the bias. Add them to the bowl with the carrots.
Use a large, sharp knife or mandoline to shred 1/4 medium napa cabbage. Add it to the bowl with the carrots and celery.
Drain the wood ear mushrooms and rinse again with cold water. Slice them thin and add them to the bowl with the other vegetables.
Crack 2 large eggs into a small bowl, add a pinch of salt, and whisk vigorously with a small whisk or fork.
Heat a large non-stick skillet or wok over medium heat. Add 1 Tablespoon of the canola oil. Pour the eggs into the pan, and cook (without stirring) until set on the bottom, about 2-3 minutes. Carefully flip the egg over don't worry if it breaks) and cook until completely set, about another minute. Transfer the egg to a cutting board and slice into 1/4-1/2" (0.5-1cm) x 1-2" (2-3cm) strips. Set aside.
Increase the heat to medium-high heat. Add the remaining 1 Tablespoon of the canola oil. Add the sliced pork to the skillet and cook, stirring very often, until it's all cooked through, about 3 minutes. Transfer the pork to a clean bowl or plate.
Reduce the temperature back to medium. Add all of the vegetables to the skillet, and cook, stirring often, until the cabbage is wilted, and the carrots and celery are just starting to soften, about 5 minutes. Add 1 Tablespoon oyster sauce and 1 teaspoon chicken bouillon concentrate or powder and stir until evenly distributed. Add the cooked pork and the sliced egg back to the skillet, and cook, stirring until everything is evenly distributed and hot.
Spread some hoisin sauce evenly over each of the tortillas. Add a scoop of the stir-fry to each tortilla, and serve as wraps. Serve with additional hoisin at the table.
Notes
You can use "black fungus, or cloud ear mushrooms" instead of wood ear mushrooms, as they're quite similar. Find them in well-stocked Asian markets with other dried mushrooms.