Add pork belly to a 12" non stick skillet over medium heat and brown until crisp on all sides and fat is rendered, about 5 or 6 minutes. Transfer to a paper towel and set aside to cool. Heat grill or grill pan to medium-high. Working in batches, place romaine halves cut-side down on grill, and cook until charred, turn once and continue to grill until slightly wilted, about 4 minutes. Transfer lettuce cut-side up to plates, and season with pepper; drizzle with dressing, and sprinkle with blue cheese and pork belly “croutons.” Serve right away.