Position an oven rack 6 inches from the broiler element and heat the broiler to high. Toss the chiles with the oil, 1/4 tsp. of the salt, and a few generous grinds of pepper. Set on a rimmed baking sheet lined with aluminum foil and broil the chiles, flipping every 1 to 2 minutes, until they brown, blister, and blacken all over, about 5 minutes total. Remove the chiles from the oven, wrap in the foil, and let cool to room temperature. Then peel off the skin and core and seed them. Cut them into 1/2-inch pieces.
Cook the bacon in a large Dutch oven over medium heat until it browns and renders much of its fat, about 6 minutes. Using a slotted spoon, transfer to a plate lined with paper towels. Add the onion and garlic to the pot, sprinkle with the remaining 1/2 tsp. salt, and cook, stirring, until they soften and brown in places, about 6 minutes. Add the cumin and cook, stirring, for 30 seconds.
Raise the heat to high, add the beer, and cook, stirring to pick up any browned bits on the bottom of the pot, until it has almost evaporated, 4 to 6 minutes. Add the chicken broth, potatoes, half of the cilantro, the oregano, bay leaf, and the chiles and bring to a boil. Reduce to a gentle simmer, cover, and cook until the potatoes are just barely tender, about 15 minutes. Stir in the pork and vinegar and cook until the potatoes are completely tender, about 10 more minutes. Season to taste with more salt, pepper, and vinegar. Serve, sprinkled with the bacon, cheese, and the remaining cilantro.