Just make the link to the disambiguation page, if there is one? Otherwise, make it a special link that doesn't go anywhere directly, but uses some javascript/CSS to raise a dialog when clicked, that gives you the different choices?
When a search term matches a tag, and none of the tagged pages have a clear "majority probability" of being correct, it would display a list of all pages with the tag, in order of popularity.
Both of these things would be amazingly annoying to the majority of Wikipedia users.
But they could be disambiguated by humans, which is my point. Humans understand context.
Whether or not something like that would be a net win for Wikipedia is up for debate I guess. That said, I think they already do have a bot that can do at least a limited amount of auto-linkification, but I can't swear to it.