Combine ricotta, powdered sugar, vanilla, espresso and cocoa powder. Stir together gently. Be sure not to over mix.
Then add cheese to a pastry bag or large plastic sandwich bag with one corner cut off.
Place cannoli shells on a tray or cookie sheet and pipe the cheese filling into sides to fill the middle and then add more to the ends. Dust with more cocoa on top and serve.
You can find chilled espresso drinks in a can at your local retailer.