Using a blender, immersion blender, or food processor, blend together bananas and coconut milk until smooth.
Stir in strawberries and pineapple, then divide mixture among popsicle molds. Freeze for at least 4 hours, until set.
When ready to coat popsicles, remove popsicle mold from the freezer and set in sink to thaw slightly.
Make the chocolate coating by melting chocolate and coconut oil together in the microwave, in 30-second increments, stirring after each time. When the chocolate is almost completely melted, stir until completely smooth. Pour sprinkles or chopped nuts, if using, into a bowl
Set a sheet of waxed paper on a cookie sheet. Remove popsicles from molds gently and carefully dip popsicle into chocolate, then immediately into sprinkles or nuts.
Enjoy immediately, or set finished popsicles onto waxed paper and freeze cookie sheet for 30 minutes, then remove popsicles to a freezer-safe container, with waxed paper between each popsicle.
Notes
Dark chocolate chips contain no milk, but check the label for vegan certification if you are concerned with cross-contamination. The melted chocolate will harden immediately when it comes in contact with the popsicle, so work quickly. Any leftover chocolate can be stored, covered, in the pantry, and reheated if it solidifies.