Line a baking sheet with parchment paper and lay out the rice cakes.
Spread an even layer of peanut butter over the top of each rice cake.
Arrange banana slices on top of the peanut butter.
Melt dark chocolate chips and coconut oil in the microwave in 30-second intervals until smooth.
Spoon the melted chocolate over the rice cakes to coat completely, then immediately sprinkle with chopped peanuts and sea salt.
Chill in the refrigerator for 30 minutes or freezer for 15 minutes until the chocolate is fully set.