Wait. The shells of cream puffs and eclairs is called pate choux in french. Here's a recipe similar to the recipe I use: http://www.marthastewart.com/349990/pate-choux it is a very straight forward and easy thing to make---might not seem so till you make it once but it really is. So you make the pate choux pastry dough by cooking it in a pan on the stove--then adding the eggs as described in the recipe--it makes a paste.
You can pipe with this stuff at this point. It's lovely to pipe with. Just put it in a piping bag and pipe the starburst designs, the design of the fireworks you want to make, like in my picture. Then bake them in an oven on a lower temperature. Now they are little golden brown light as air starburst shapes.
Then you color some granulated sugar in the firework colors you want.
Then beat some egg white and water to brush on the baked starburst so when you sprinkle on the sugar that you colored it will adhere to the surface. You probably could use piping gel too
The 'fireworks' are very lightweight and so you can stick a wooden skewer in them or a spaghetti noodle in there to get them 'up above the cupcake like real fireworks.
I hope this is more understandable. If this interests you I'll be glad to fill in any gaps in my directions.
That recipe I linked to gets a little fussy when you go to make the cream puffs (click on the thumbnail picture at the bottom of the recipe for those more inticate baking instructions)----I just pipe the designs I want and bake them about 325 or 360* till they're done--depending on the size of the project. They will be crisp and fully cooked when they come out of the oven.
*fareneheit of course, sorry.