Arrange paper liners on a sheet pan. Melt the chocolate and coconut oil in the microwave until smooth. Drop about 2 teaspoons of melted chocolate into each liner. Spread to cover the bottom of the liner. Freeze for 4-5 minutes.
In a mixing bowl combine the yogurt, peanut butter, vanilla, and maple syrup together. Spoon about 1 tablespoon of the yogurt into the chocolate shells, top with a banana slice and pour over the remaining melted chocolate to cover the yogurt. Sprinkle with flaky sea salt if desired.
Freeze until firm, about an hour. Enjoy immediately or store in the fridge/freezer for 3-4 days.