Line a small baking sheet with parchment and set aside. In a medium bowl mash the ripe banana with a fork until mostly smooth with a few small lumps remaining.
To the mashed banana add the almond butter, maple syrup and vanilla extract. Stir vigorously with a spatula until the mixture is glossy and homogeneous.
In a separate bowl whisk together the oat flour, protein powder, cinnamon and salt. Pour the dry mix into the wet banana mixture and fold with a spatula until it becomes a thick, slightly sticky dough. Fold in the mini chocolate chips last.
Cover the bowl and refrigerate the dough for 15–20 minutes to firm it up — chilling makes portioning and rolling much easier.
Use a small cookie scoop or tablespoon to portion the chilled dough into roughly tablespoon-sized mounds. Roll each mound between your palms into a smooth ball and place on the prepared sheet. You should end up with about 14 bites.
Transfer the tray to the freezer for 10 minutes to set the exterior so they hold their shape when coated.
While the bites firm up, melt the chocolate and coconut oil together using a double boiler: simmer a small pot of water, place a heatproof bowl on top (not touching the water) and stir the chocolate and oil until smooth. Remove from heat and let cool for 1–2 minutes.
Working quickly, dip each chilled ball into the melted chocolate using a fork, letting excess drip back into the bowl, then return to the parchment. Alternatively, for a lighter coating, use a spoon to drizzle the chocolate over half of each ball. Immediately sprinkle with a pinch of flaky sea salt before the chocolate sets.
Place the coated bites in the fridge for 10–15 minutes until the chocolate is firm. Store finished bites in an airtight container in the refrigerator for up to 1 week or freeze for longer storage.