How to Make It
Slice the pork across the grain 1/4 inch thick. Arrange the slices on 2 large rimmed baking sheets in an even layer. In a small bowl, mix the paprika with 2 tablespoons of salt and 2 teaspoons of black pepper. Sprinkle the seasoning mix evenly on the meat and let stand at room temperature for 30 minutes.
Meanwhile, in a large enameled cast-iron casserole, heat the oil. Add the bay leaf and cook over moderate heat until lightly browned, about 2 minutes. Add the onion and a generous pinch of salt and cook, stirring occasionally, until the onion is browned, about 10 minutes. Using a slotted spoon, transfer the onion to a bowl; leave the bay leaf in the casserole.
Add the garlic, oregano and crushed red pepper to the casserole and cook over moderately high heat, stirring, until fragrant, 1 to 2 minutes. Add the wine and simmer until evaporated, 5 minutes. Add the stock and roasted bell peppers and bring to a boil. Discard the bay leaf and oregano. Transfer the mixture to a blender and puree until smooth.
Return the red pepper broth to the casserole. Add 4 cups of water and bring to a boil. Season with salt and black pepper. Add the marinated sliced pork and simmer over moderately low heat until very tender, about 1 hour.
Put the cheese on the roll bottoms. Top with the pork and onion and drizzle with some of the red pepper jus. Close the sandwiches and serve.