Thanks for pointing this out.
It would be really useful if such an option is present as a built-in functionality. But it is not possible at this time.
You've noticed right, that SearchManager.Search
is responsible for the snippet construction, but it would take a lot effort to override it and change the method implementation. You can change the meta fields for a certain module by modifying the web.config but this could also affect the information that would be indexed.
the Telerik team