I am making my first tiered cake tomorrow, and I have a question. I have made fondant toppers before, I have to use water to get the powder sugar off the fondant, which makes it all sticky. How can I get the sugar off the fondant without making it sticky?

I've had that problem in the past ...I use my regular iron on the steam setting to steam it off. If you have a regular clothes steamer that works too.
But I've also learned that you could use a light coating of shortening to help get the sugar off. HTH

if you use corn starch instead of powdered sugar to roll out your fondant on, you can easily wipe away the residue.

I use a large 3" paint brush if I have to brush the ps off. Try using less ps when rolling your fondant out. I really don't use that much and don't have this problem very often.

What I learned when I was first starting out was to put your PS in a new knee high and tie off the end to use as a sifting bag. The sugar can then be dabbed on lightly. Now I don't use powdered sugar at all. I roll my fondant out betweeen two vinyl mats with just a dab of shortening. You can roll it out thinner and you can use the mat to help you lift it on to the cake.

I use cornstarch instead of P sugar as thats what I was taught and prefere. I also add a very light coating of shortening on my mat/board before rolling.
I also have a round fluffy pastry brush that works great too. Its good for the small imprinted areas you can't really clean out any other way.

I use cheesecloth to make my puffs or daubers. Cut a small square of cheesecloth, double thickness, add a good heaping tablespoonful or so of cornstarch, or PSugar if thats your preference, in the middle, gather the ends together and bind it all up with an elastic band. Simple and effective. Just puff or daub on your mat/board/countertop until you have a light dusting. Using a puff, you don't have to worry about using too much.

I'd steer clear of the water except for attatching fondant to fondant. To much chance of ruining all your hard work!

Thank you all very much! I had no idea and had been using water and vodka, lol. Poor kids.......