The out of the box Login widget that can be dropped onto a Sitefinity page provides the ForgotPassword functionality, however if you need to use it as a separate widget, I believe you might find the discussion we've had on this forum thread
useful. Please do not heasitate to get back to us if you need some additional information, we'll be glad to help.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items