So this is far from simple to achieve, I'm sure that Microsoft will bring a easy interface at some point but in the meantime you can dig around in SharePoint to find the data and restore it.
- Add a new page and edit it, we need to make sure the wiki has been recently changed to allow us to find the hidden list in a later step. Just add a new page and some words, you can remove it later.
- Navigate from Teams to the associated SharePoint site, clicking on the files tab then Open in SharePoint is a good route.
- Now you are in SharePoint, look for the Cog at the top, and choose Library Settings
- Now look in the left most column, you'll see a list of parts of the site, at the bottom is a section called recent. Under recent there should be some long looking number starting with 19:, this is the hidden list that contains your wiki, click it
- Now you'll see a list of items, these represent the various elements of the wiki, click on the words that say 'Page' and look at the detail on the right, find the entry that has wikiTitle matching your lost page, look down the list for the value wikiDeleted which you'll see says Yes.
- Click that with the mouse and it'll turn into a toggle you can now turn to No
- Go back and look for your page in the Wiki
If it was the page you deleted then this should be it, the sections don't seem to be changed to deleted but you could always repeat the process.
Good Luck! I'm sure this isn't supported, and you probably could do all kinds of damage to your wiki from the list, so be super careful.
