What are good openings for White during a blitz game? It seems as though White can easily dominate the tempo in a blitz game through a strong, aggressive opening. Is this the case? What openings are strong for White when there is a short time limit (e.g., in blitz)?
I think this depends very much on how strong you are. 

That said, I had some success with the Ponziani. It is not the "best" opening, but solid, and many players don't know it and lose some time thinking about the next moves. The theory is easy, and there are several traps black can fall into (my favorite is when black takes the "unprotected" e4 pawn with the knight and you can fork it with Qa4+). 

Generally it might be a good idea to play aggressive (e.g. Steinitz' Qh4 in the Scotch game) and to try to throw the opponent out of the book as soon as possible. Of course the opening must be still playable, and you need to know some theory.