That depends on what you consider a small batch
I personally find it almost impossible to whisk less than 250gr of confectioners sugar, not even with a hand-held device. You need a certain amount of material. So this is what I would recommend:
250gr confectioners sugar
15gr of dried egg whites or meringue powder
35-40ml of water, depending on air humidity
Beat for about 5-7 minutes on high speed with hand-held device
That gives a medium consistency icing. If you want to pipe flowers or the like, you need less water, for flooding more.