To make the pork belly, preheat the oven to 250 F. Put all ingredients in a Dutch oven, cover and bake for 4 hours. When pork belly is soft, remove from the oil and let cool to room temperature. Chill until ready to make the sandwiches.
To make the yuzu dijonaise, put all ingredients in a blender and blend until smooth. Refrigerate until ready for use.
To assemble the sandwiches, slice the cooked pork belly into 1/2-inch pieces and sear in a nonstick pan on both sides.
Spread a generous amount of yuzu Dijonaise on both sides of each roll. Cover the bottom with a layer of pickles, followed by the cheese, sliced ham and the pork belly.
Add the top bun and toast in a panini press until the bread is slightly browned and the cheese is nicely melted. Cut in half and serve immediately.