Stick that in your pipe and smoke it, fourth grade science teacher!

Growing up, teachers would love to point out the fallacies of Star Wars. A common favorite is that ships wouldn’t explode in the vacuum of space. But let’s think about that for a moment…
What would lead us to believe that space is a vacuum in that galaxy far, far away? When they are dogfighting, ships seem to steer gracefully, as if in an atmosphere. You can apparently park a ship in an asteroid field and then go out for a stroll with minimal protection. X-wing cockpits look flimsy enough that I almost expect the pilot to be able to open the window. The aforementioned explosions in space…
I think we have to face facts. There is no vacuum in space. There is air. I can grant you that there isn’t a lot of air, but there is something out there.
Could someone please point out to me where there is concrete evidence of a vacuum?