Line a baking sheet with parchment paper. Set aside.
In a clean and dry medium heatproof bowl, add the chocolate chips and oil. Set the bowl over a pot of 1-inch deep simmering water. Cook until the chocolate is melted and smooth, stirring occasionally.
Meanwhile, quickly cut the bananas into ½-inch thick slices.
When the chocolate is melted, remove from heat. Let the water to continue to simmer. Add one banana slice into the chocolate. Use a fork to move the banana around gently and get it cover with chocolate completely. Lift the banana up and scrape it against the side of the bowl to remove excess chocolate. Transfer the banana along with the fork to the prepared baking sheet. Slide the banana off the fork with a gentle push of a finger.
Repeat with the rest of the banana slices. If the chocolate get solid again, place the bowl of chocolate back on the pot of simmering water. Cook until the chocolate is loose again.
Transfer the baking sheet to the freezer and freeze for at least 6 hours. Once frozen, transfer the bites into a freezer container. The bites can be kept for 3 months. Serve without thawing.