Peel your bananas and slice each one in half crosswise, then in half again lengthwise, so you end up with four pieces per banana. Push a popsicle stick into the flat, cut end of each piece so it has a sturdy handle. Lay all the pieces on a parchment-lined baking sheet, spacing them so they aren't touching each other.
Slide the baking sheet into the freezer and let the banana pieces firm up for about 1 hour, or until they feel solid to the touch. I like to use this waiting time to melt my peanut butter coating, so nothing goes to waste. Frozen bananas also hold their shape much better once dipped.
In a microwave-safe bowl, combine the peanut butter and coconut oil. Microwave in 20-second bursts, stirring between each one, until the mixture is completely smooth and pourable. Stir in the pinch of salt at the end so it doesn't clump while melting.
Remove the bananas from the freezer and dip each piece into the warm peanut butter mixture, turning it so the coating wraps evenly around the banana. Let any extra drip off over the bowl before setting the piece back on the parchment. Return the tray to the freezer for about 15 minutes so this layer can set.
Melt the white chocolate chips in a separate bowl in short microwave bursts, stirring often so they don't scorch. Dip each peanut butter-coated banana into the white chocolate, letting it drip back into the bowl before placing it back on the tray. This second coat is what gives the ghosts their classic pale, spooky look.
While the white chocolate is still soft, press two mini chocolate chips into the top of each banana to form the ghost's eyes. Freeze the finished ghosts for another 15 minutes so everything sets firmly before you serve them.