Mix sea salt, 1/2 teaspoon cinnamon, 1/4 teaspoon cloves, 1/4 teaspoon black pepper, nutmeg, and garlic salt together in a bowl. Rub salt mixture all over pork shanks.
Heat 2 tablespoons olive oil in a large saucepan. Cook pork shanks in the hot oil until browned, 2 to 3 minutes per side. Pour in enough water to cover the shanks. Stir in coarsely chopped onion and celery. Bring to a boil; reduce heat and simmer until pork can be easily removed from the bones, 2 to 3 hours.
Transfer pork shanks to a cutting board; shred pork.
Strain cooking liquid, discarding bones, onion, and celery. Pour strained liquid back into the saucepan. Stir in shredded pork.
Mix ground pork, finely chopped onion, parsley, 1/4 teaspoon cinnamon, 1/4 teaspoon cloves, ginger, mustard powder, salt, and 1/4 teaspoon pepper together in a large bowl. Shape into balls.
Pour toasted flour into a shallow dish. Roll meatballs in toasted flour.
Heat 2 tablespoons olive oil in a large skillet over medium-high heat. Cook meatballs in batches until browned, about 1 minute per side.
Stir browned meatballs into the shredded pork stew. Simmer, stirring in leftover toasted flour, until meatballs are no longer pink in the center and stew is thick, about 30 minutes.