1. Put the dark chocolate in a metal (or other heatproof) bowl, and set it over a saucepan of barely simmering water. (Do not allow the bottom of the bowl to touch the water.) Stir occasionally until the chocolate is melted and smooth.
2. While chocolate is melting, assemble ice cream sandwiches. Break each piece of frozen cinnamon toast into 4 mini toasts. Add one heaping tablespoon scoop of ice cream to a toast and top with another piece of toast. Press together and smooth sides with spoon.
3. Place on a baking sheet lined with parchment paper and keep in freezer.
4. When chocolate is melted, quickly stir in 1/2 teaspoon of ground cinnamon. Dip each assembled cinnamon toast sandwich into the chocolate.
5. Return to parchment lined pan and keep in freezer until hardened, about 20 minutes. Keep frozen until ready to eat.