Here's a list of shortcut keys that the current version of The Report Viewer (v8.47.520.0) accepts.
DEL Automation Stop F11 Full Screen F5 Full Screen Escape Full Screen Exit D Tab Right Drill Down A Tab Left Drill Down W Close Drill Down Ctrl R Refresh Ctrl P Print Ctrl C Copy Ctrl T Toggle Side Panel Ctrl F Find Ctrl O Open Ctrl S Save Right Next Page Left Previous Page Oem Close Brackets Next Page Oem Open Brackets Previous Page Down First Page Up Last Page