In a medium bowl, whisk together hoisin sauce, rice wine, low sodium soy sauce, rice vinegar, minced garlic, grated ginger, cornstarch, sesame oil, black pepper, and optional mirin until smooth. Set aside ½ cup of the marinade for later use.

Slice the pork tenderloin into thin strips, about 1/3-1/2 inch thick. Combine the remaining marinade with the sliced pork in a bowl and let it marinate for at least 10 minutes.

Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Pour in the beaten eggs and cook for about 2 minutes until set. Remove and slice into strips.

In the same skillet, add another tablespoon of vegetable oil, remove excess marinade from the pork and stir-fry for 2-3 minutes until cooked through. Set aside.

Return the skillet to medium-high heat, add another tablespoon of vegetable oil, and stir-fry the coleslaw and mushrooms for 3-4 minutes.

Lower the heat, return cooked pork and egg strips to the skillet, drizzle with the reserved marinade and toss gently to combine. Cook on low heat for 1-2 minutes.

Remove from heat and spoon the Moo Shu Pork into serving dishes, garnishing with sliced green onions. Serve promptly with warm tortillas or Chinese pancakes.