The standard Skuid Lightning Page component does not have configuration options like this. Its a good suggestion - or we might also just ensure the background is transparent during loading.

You can call a skuid page from your own Lightning Component. I’m guessing that you could define the background color parameter of the component there. Here are docs about that method: https://docs.skuid.com/latest/v2/en/skuid/deploy/salesforce/lightning/#creating-the-lightning-component-bundle

Many thanks for the suggestion Rob, I will try with a Lightning Component