Peel the bananas and slice them into 1-inch thick rounds. Place the banana slices on a parchment-lined baking sheet.
Using a small spoon, add about 1 teaspoon of peanut butter on top of each banana slice. Top half of the slices with another banana slice to create little sandwiches.
Freeze the banana sandwiches for about 1 hour, or until firm.
In a microwave-safe bowl, combine the dark chocolate chips and coconut oil. Microwave in 30-second intervals, stirring in between, until melted and smooth.
Remove the banana sandwiches from the freezer. Dip each sandwich into the melted chocolate, ensuring it’s fully coated. Use a fork to lift it out and let any excess chocolate drip off.
Place the chocolate-coated sandwiches back on the parchment-lined baking sheet. While the chocolate is still wet, sprinkle with chopped salted peanuts and a pinch of sea salt.
Return the baking sheet to the freezer for another 30 minutes to set the chocolate.