In a medium bowl, whisk together the rice vinegar, 1 tablespoon of honey, and sea salt until the honey and salt are fully dissolved.
Add the julienned carrots and daikon radish to the vinegar mixture, tossing thoroughly to coat, and set aside to quick-pickle for at least 20 minutes.
Slice the pork tenderloin into thin, wide strips roughly 1/4-inch thick to mimic the traditional shape of pork belly.
In a small bowl, whisk together the tamari, the remaining 1 tablespoon of honey, minced ginger, minced garlic, and black pepper to create the glaze.
Heat the sesame oil in a large non-stick skillet over medium-high heat and sear the pork strips for 3-4 minutes per side until deeply golden and cooked through.
Reduce the heat to low, pour the tamari glaze over the pork, and simmer for 2 minutes until the sauce reduces to a thick, glossy consistency that coats the meat.
Steam the bao buns in a bamboo steamer or microwave according to package directions until they are soft, hot, and pillowy.
Assemble the buns by placing two glazed pork strips into each, followed by a generous portion of pickled vegetables, fresh cucumber slices, and a sprinkle of sliced green onions.