Peel the bananas and slice them into 1-inch thick rounds. Arrange the banana slices on a parchment-lined baking sheet.

Using a small spoon, place about 1 teaspoon of peanut butter on top of each banana slice. Top with another banana slice to create a sandwich. Repeat until all banana slices are used.

Place the baking sheet in the freezer for at least 1 hour, or until the banana sandwiches are firm.

In a microwave-safe bowl, combine the dark chocolate chips and coconut oil. Microwave in 30-second intervals, stirring in between, until the mixture is smooth and fully melted.

Remove the banana sandwiches from the freezer. Dip each sandwich into the melted chocolate, ensuring it is 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 chopped salted peanuts and a pinch of sea salt on top.

Return the baking sheet to the freezer for another 30 minutes, or until the chocolate is set.

Serve immediately or store in an airtight container in the freezer for up to 2 weeks.