Make the seasoning paste: In a small bowl, stir together garlic, sweet paprika, oil, and smoked paprika.
Make the pork: Using the tip of a sharp knife, prick pork all over. Using your fingers, rub seasoning paste all over pork. Transfer to a large bowl. Add wine and bay leaves and turn to coat. Cover and refrigerate overnight.
When you are ready to cook, preheat oven to 325°F (160°C). Remove pork from refrigerator and let stand at room temperature for 30 minutes. Using a slotted spoon, remove pork from marinade, reserving marinade. Pat pork dry with a paper towel and set aside on a plate.
In Dutch oven, heat oil over medium-high heat. Add pork, in batches, and brown on all sides, about 4 minutes per batch. Transfer to a plate as completed and set aside.
Reduce heat to medium. Add onion to pan and cook, stirring, until softened, about 3 minutes. Add chorizo and toss well. Add reserved marinade, and tomatoes and juice, and bring to a boil. Boil for 2 minutes. Return pork to pan and season to taste with salt and black pepper. Cover and transfer to preheated oven. Bake until pork is very tender, about 1 hour.
Add clams to pan, arranging evenly over pork. Cover and bake until clams have opened, about 7 minutes. (The cooking time will depend on the size of the clams.)
Remove from oven. Discard bay leaves and any clams that have not opened. Garnish with parsley and serve immediately.