Set a large pan over medium-high heat. Add vegetable oil and heat until shimmering, about 2 minutes. Add diced onions and sauté until light brown and beginning to caramelize, about 7 minutes. Reduce heat to low and add the ground pork. Cook, stirring often, until cooked through, about 10 minutes. Add scallions, ginger, and garlic and cook 5 minutes.
Raise heat to medium, and add black bean sauce, tianmianjiang, and shallot sauce. Cook 5 minutes until the sauces reduce and start to stick to the pan, then add black vinegar and rice wine to deglaze. Add sugar and black pepper and stir well, then add chicken stock. Bring to a boil, then reduce to a simmer and cook about 20 minutes. Stir in half the cornstarch slurry to thicken, then turn off heat and stir in the rest.
Meanwhile, cook the wheat noodles according to the package directions. When they are ready, transfer to a bowl, mix in the sauce, and serve.