I am using a small wacom tablet. I go to draw a circle and the selection options pop up every time. I'm pretty new to Krita but surely I should be able to draw a circle without this happening? I'm not touching any other buttons to trigger a shortcut, just using the pen to draw.

Sounds like you've changed the settings in the wacom tablet settings app to add a left-click to pen-down. Or something like that... This doesn't happen in Krita by default in any case.

Where would I change this? It's a new tablet so I haven't fiddled much with the settings. I do not remember this problem on my Macbook either. It's only on my Win 10 PC.

Yes, it's a windows only tablet flicks thing: https://docs.krita.org/en/user_manual/d ... up-palette

You will need to search around for it's location in windows 10 settings, because I myself haven't got a windows device and haven't seen it in forever.