It's not really safe to hoover electrical components, no. Hoovering the fans should be fine but I wouldn't advise going all gung ho on the rest. There's not only the risk of static damage but also the risk of direct damage because you're a badly coordinated ape.
Your PC case is essentially a hover, the only difference is the case is metal and plugged in to the ground. In reality though it's safe to hover home PC stuff, you've got things made to handle by home users it's not a quantum computer, I've been hovering PCs for decades and yet to have anything fail as a result. If you're even remotely worried just have the compnants resting on a plugged in metal case so the board is earthed at all times.
Use compressed air, its cheap as chips and good fun too! you'll end up wasting half the can spraying people in the face with it!
But somehow, you still need to collect the dust that is being removed, otherwise it just ends up back in your case.