Add the Greek yogurt, banana, spinach, frozen pineapple, and honey to a blender. Blend until the mixture turns smooth and evenly green with no large spinach pieces left.
Line a baking sheet with parchment paper. Pour the blended mixture onto the paper and spread it into an even layer about half an inch thick.
Scatter the blueberries and kiwi slices across the surface. Press them lightly into the yogurt so they stay in place once frozen.
Place the baking sheet in the freezer for at least four hours or until the bark feels completely solid.
Remove the sheet from the freezer and break the bark into pieces with your hands or a knife. Serve the pieces right away.