Hi,
One sure way to achieve it would be to
1. Copy and rename the skin you are using.
2. In Administration > Site Settings, enable per page skins and
3. then in page settings of the blog page you will see where you can set a page specific skin, slect the copy you just made
4. Edit the layout.master of the copy and remove the Menu or PageMenu from inside the divLeft
For some skins it may be easier, for example if the main menu is on the left anyway like in mitchinsone-eathy-alt1 or jsavard-mojoportal, then these steps will work
1. Go to Administration > Site Settings
2. Enable Hiding Menu on Pages
3. Go to the Page Settings for your blog page and check the hide menu box
Hope it helps,
Joe