Dragon attack.

I'm interested in the question about the Fairy Dragon... specifically, its Cold Ring attack. The thing is, when I attack with the Cold Ring, I have to hover the cursor over the enemy unit, and if that unit is small – a single-unit creature – the ring doesn't hit it, and the turn is wasted.
At the same time, the computer-controlled dragon manages to cast the ring in an empty space, let's say in front of the target, and thus damage it. Can a player cast the ring in an empty space as well?