We're using the following CSS at dynarch.com:

div.dynarch-menu-noicons tr.item td.icon img,
div.dynarch-menu-noicons tr.item td.icon div { width: 5px; }
div.dynarch-menu-noicons tr.item td.icon { width: 5px; }

And add class="dynarch-menu-noicons" to the UL-s that define menus where we don't want icons.  The reason for it is that I still like some spacing.  The History menu uses this style (this menu appears if you viewed several different pages in our website).

Try the following CSS to hide them completely:

div.dynarch-menu-noicons tr.item td.icon { display: none }
div.dynarch-menu-noicons tr.item td.arrow { display: none }

(make sure you include this CSS after loading the menu skin.)

Hope this helps.