Put the almonds in a food processor for about 2 min. to pulverize them. You want the grain to be fine but not a flour.
Put the ground almonds in a bowl, add the cocoa and mix well.
Add the San Marzano and mix well until you have a soft paste.
Put the sugar in a flat dish.
Take a small lump of the paste, roll it in your hand to make a ball, then roll the ball in the sugar and set on a clean plate.
Roll all your balls, refrigerate for about 1 hour and serve cold.