Put the oven rack in the upper middle position, put a pizza stone (or baking sheet) on it and preheat to 475 degrees F.
To make the sauce, just mix the gochujang with enough kimchi juice so that it's thin enough to easily spread (but not watery). Add the sesame oil and garlic and stir to combine.
On a well floured surface, roll the dough out until it is less than 1/4" thick. Dust a pizza peel (or wooden cutting board) with course ground cornmeal and lay the dough on top. I used a special pizza pan for my toaster oven so I made the pizza directly on the pan.
Use a spoon to spread the sauce on the dough.
Top the sauce with a thin layer of cheese
Top with cheese with the sliced pork belly and kimchi
Top with the remaining cheese and scallions
Gently transfer the pizza to the preheated pizza stone and bake until the crust is golden brown. Remove from oven, garnish with cilantro, slice and enjoy!