Great thanks to user "Patthe" who helped to find the root cause and provided the below screenshot of the Settings page.
For ASUS Prime with Android 4.x, "right-click" is supported. However, you need to take note of the setting for "right-click." Within the "Settings" screen, click ASUS customized setting on the left side. Click Right button behavior in the TOUCHPAD/MOUSE section, then make sure Show context menu is selected as shown below.