Please note first that changing to the left click isn't practical and may conflict with another key binding, like the menus.
But you can use ccsm
to initiate another key for showing the mouse location:
If you don't have ccsm
: Install From Here
You also need the package compiz-plugins-extra
. You can find it in the Ubuntu Software Center.
Go to CompizConfig Settings Manager > Accessibly > Show Mouse:
- Under
Use This Plugin
left menu: check Enable Show mouse
.
- Change the mouse
Initiate
key binding as below.

To determine the meaning of Compiz button numbers, check this answer.
- Button 1 is generally the Left click
- Button 2 is generally the Middle or Right click
To take effect, you might need to "restart" Compiz:
compiz --replace &