To open Excel via the "Run" dialog using the Windows key + R shortcut, follow these steps:
1. Press the Windows key + R on your keyboard to open the "Run" dialog.
2. In the "Open" field of the "Run" dialog, type "excel" (without quotes).
3. Press Enter or click "OK."
This will open Microsoft Excel on your computer. It's a quick and handy way to launch Excel without going through the Start menu or desktop shortcuts.