Add dates, water, ground almonds, cocoa, butter and cinnamon to a tall container and puree with the hand blender. Form approximately 20 balls from the mixture.

Coarsely chop the chocolate and melt it in a bowl above a bain-marie. 
 

Dip the date balls into the chocolate one at a time using a fork and wipe off any excess couverture on the edge of the bowl. Place the pralines on parchment paper, sprinkle with the pistachios and refrigerate for approximately 30 minutes.