In order to expand an item in a List ,you need to know in which item the search text was found.
A solution is to add the search query in the search result links. For example if the user searched for sometext you can add a query parameter to every link in the search result (/yourPageFAQ.aspx?query=sometext ).
1. In the SearchResult control add a query string parameter (for example called query) for every result link.
2. You need to override the Telerik.Lists.WebControls.ListDisplay control to expand a specific list item, based on the query parameter.
I hope this helps you.
the Telerik team