Place the ricotta cheese into a fine mesh strainer and place it in the fridge to drain for at least 12 hours and up to 24 hours.
In a large bowl, combine the drained ricotta cheese, confectioners’ sugar, 1/4 cup of the mini chocolate chips, vanilla extract, and orange zest (if using); mix well.
Using a spatula, carefully scrape the mixture into a pastry bag fitted with a 1/2 inch open tip. Use at once, or refrigerate until needed; filling can be made up to 24 hours in advance.
When ready to serve, pipe the filling into one end of the cannoli shell, filling shell halfway, then pipe into the other end. If you don’t have a piping bag, you may spoon the filling into the shells. Repeat with remaining shells.
Place the remaining mini chocolate chips on a small plate. Dip each end of the cannoli into the chocolate chips, then lightly dust with confectioners’ sugar. Serve at once.