The https://www.cloudflare.com/partners page says:
Plus, we’ve made integration into any hosting control panel straightforward. We offer integrations for cPanel, WHMCS, Odin Plesk Panel 12 and above, Interworx and ISPSystems, which means that if you’re using one of these control panels, you can get started with CloudFlare within five minutes. Alternatively, if you’re using a custom control panel, we have an API for integration.
Would love to see Webmin/Virtualmin in that list. For now all that I could find on virtualmin.com related to Cloudflare was this discussion of 4 years ago: https://www.virtualmin.com/node/24036