Special equipment: cheesecloth and a large piping bag fitted with a large tip
Place a piece of cheesecloth in a strainer and hang it over a bowl. Add the ricotta to the strainer and cover it with a bit more cheesecloth. Place a small plate over the top of the ricotta and weigh it down with a large can of tomatoes or anything heavy. Let it strain in the fridge overnight.
In a large bowl, add the strained ricotta, powdered sugar, candied orange peel and vanilla. Stir everything so it's all well mixed.
Add the filling to a large piping bag fitted with a large tip. Pipe the filling into the cannoli shells and dip each end in the mini chocolate chips. Sprinkle over some powdered sugar. Serve right away for best-tasting cannolis.