In a blender or Vitamax combine the dates, nut butter, maple syrup, coconut oil, vanilla extract, sea salt, and cinnamon. Puree the mixture until it is relatively smooth. If you are using a blender, you might want to use a tempter.
In a bowl combine the crispy rice and hemp hearts together. Add the date mixture and using your hands, knead it a little so it all comes together.
Press the rice mixture into a parchment-lined loaf pan or a square baking dish (shape doesn't really matter here). I find using a spoon helps to press the mixture into the corners.
Chill the pan of rice mixture while you melt your chocolate.
In a Bain Marie or microwave, melt the chocolate just until no clumps remain.
Pour the chocolate over the chilled rice base and then return the bar to the fridge to fully set.