Bring meat to room temp and preheat oven to 300ºF.
Season the meat with salt and pepper. Combine the paprika with 1 teaspoon Mexican oregano, 1/3 palmful, with fennel and granulated garlic. Rub spices into meat.
Place pork in a roasting pan, top with sliced onion. Add beer to pan and cover tightly with foil. Roast pork 4-5 hours until very tender. Cool to handle and shred.
Heat a Dutch oven over medium-high heat with oil. Add chopped onions and sliced garlic to pan and season with salt and pepper, remaining teaspoon Mexican oregano, cumin and coriander. Process tomatoes in a food processor until smooth. Add stock, tomatoes, hominy and pinto beans to the pot Add the shredded pork and reserved pan juices. Simmer to thicken and combine flavors, 30-40 minutes.