Hi Richard
If you only want to open the hyperlink field in a new window, it is already supported in later version of QuickApps. Define your Display Fields property and include the field that is of hyperlink type, edit this field and notice there is an option named "Open Link In" and you can specify value as "New Window". That should do it.
Before this feature is available, you can also use Custom Field and specify Calculated Value something like using field expression to fill in the href value and display value for the anchor.
<a href="<%Target Url%>" target="_blank"><%Text%></a>