Place wings in an 8 quart pan; cover with stock; bring to simmer over medium heat. Cook, skimming foam, until the stock is reduced to about 8 cups, 3 to 3 1/2 hours. Remove from heat, pour through fine strainer, discard solids; reserve stock.
Heat oil, chopped scallions, ginger, and garlic in a 12 inch skillet over medium-high heat. Cook, stirring occasionally, until fragrant, about 2 minutes.
Add pork and tobanjan; cook until pork is cooked through, 3 to 4 minutes.
Add reserved stock, soy, sugar, sesame paste, and salt; boil. Reduce heat to medium; cook, stirring, for 3 minutes more; keep warm.
Meanwhile, bring a pot of salted water to a boil. Add noodles; cook, until tender, 2 to 3 minutes, drain, and divide between 4 deep serving bowls.
Ladle broth over each bowl of noodles, and garnish with scallions and some rayu, if you like.