Yup you can and try and catch it with a net or suck it up with the baster.
I am pretty sure they are, the only algae that easily blows off the rocks, the other hint is the small air bubbles trapped in the algae. The first time I got them was a result of me moving the aqua scape around, the second time was when I upgraded to a new tank. I found no solid answers of what causes Dinos when I was researching them. They will also re-appear in a few hours. If they do then definitely Dinos.
Going to try the H2O2 method.
Just dosed 10ml