Appian Solution for Previewing PDF Data in Paging Grid and Download Option" in another Tab.

A record action allows you to open the start form of that process in a new tab. You could use that to just display the document. When you omit the submit button, the process will never be started and not cause any load on the system.

My normal approach is to just load the Doc ID into a local variable and then show this in a Document Viewer Field opened on the same form - here there's not really any need for "in another tab" (aside from the fact that in this simpler approach, it wouldn't really work).  The option to download is inherently contained in the PDF preview field (though i guess that can be browser-specific).