I made cupcakes last night and cooled them. I then stored them---first mistake---in an airtight container....now they are too sticky to frost.
What do I do?
How do you want them to look? Wouldn't you be able to just frost them in a swirl using a star tip of some size?
That's what I would do. Use a big star tip and make a pretty swirly on top. It is way faster to frost them that way too.
I would let them "dry out" a little. I tried to make a cupcake bouquet once with sticky cupcakes. I put it together and piped the frosting on. Several hours later when I walked back into the kitchen the fosting had slipped off of most of the edge cupcakes. But, if you are just going to let them sit flat you should be OK, and they will be nice and moist!