Sure. From inside the administration console you'll want to select "Manage System Settings" on the left hand side. Then select "Skin Manager."
This will take you to a screen where you can select the skin that you want to use. We are currently only shipping with one skin. If you select that skin you will have an option to download it. Once you have it downloaded you can make the modifications that you would like.
To use your new skin you'll want to go back to the Skin Manager and Import the skin. When this is completed you should be able to select your new skin from the list and apply it to the site.
In future releases we do plan on improving these tools.