You might want to take a look at DNNCreative.com for skinning help, but removing the menu isn't hard. Simplest way is to directly edit the .ascx file for the skin you use. It will normally be in /Portals/_default/Skins/{SkinName}/{PageSkin}.ascx. The names will depend on your skin and which one you use for that page, so if you used the DNN Blue skin and the Horizontal Menu - Full Width page skin, then it would look like:
/Portals/_default/Skins/DNN-Blue/Horizontal Menu - Full Width.ascx
In that file you'll see a line with something like:
"<dnn:NAV runat="server" id="dnnNAV" ..."
Assuming you're using the current DNN NAV menu. You need to remove that control, from the <dnn:NAV to the /> at the end of it.
That removes the control, but not the table cell or whatever it was in. You would need to do more editing of the skin if you need to change this, for that you'll need to have at least some basic skills of skin editing.
Jeff