I want to unroute my board and run the autorouter again. I've noticed when I do this the vias are still there. I just added a PWR and GND copper pour and they are full of holes too. How do I remove all the vias, without having to go do them all manually, and get my copper pour layers back to solid?

Unroute command should remove all vias from traces but leave vias not connected to any trace. If it does not do that, please check that you use latest build and if that's case send the PCB file to support@diptrace.com
Anyway, you can remove all vias at once. Please use "Edit/ Edit selection" to select all vias, then delete them using Delete key.

It works as described. Didn't know about the Edit Selection option, nice. Then Update the copper pours and I'm good.

Thanks!