In the Wiki tool, you can't delete a wiki page, but you can make it inaccessible by editing its permissions and removing any internal links that reference the page.
To make a page inaccessible by editing its permissions:
Enable/Disable on this page?, uncheck the boxes in the
To remove internal links to a wiki page:
[ ]) and the text inside them.
Source: Indiana University's Sakai Knowledge Base, https://www.indiana.edu/~sakaikb/display.cgi?docid=aues