Preheat oven to 350 degrees F and lightly coat an 8x8 baking pan with oil (or butter, if not vegan).
In a high-powered blender or food processor, toss the black beans, coconut oil, and dark chocolate. Blend until smooth, then add the flour, sugar, flax egg, and baking soda. Pulse until just combined.
Transfer the batter to the 8x8 baking pan and bake for 20-22 minutes. Sprinkle the caramel pieces and dark chocolate chunks over the top bake for an additional 1-2 minutes. If a toothpick comes out clean, remove the brownies from the oven and cool before serving. Sprinkle with sea salt.