What, why would you want to do that? Sorry little Modern UI vs. desktop joke there for you. Welcome to the club
It will depend on which Surface you have but as DOS pointed out legacy apps (desktop programs that run on previous Windows versions) will only open in desktop and Modern UI apps (those acquired through the app store) will only run in Modern UI.
If you have a Surface RT there are a few apps that are included, such as Office, which are actually desktop apps and will take you to the desktop if launched from the Start screen. You are not able to install any more of these legacy apps on the Surface RT. All other apps must come from the app store and will be Modern UI apps which run from the Start screen.
If you have a Surface Pro any programs you install in the traditional way (legacy apps) will only open in the desktop but can be launched from a shortcut tile on the Start screen. You are not restricted from installing additional legacy apps as you are on the Surface RT. You can also install Modern UI apps from the store and these will only run on Modern UI from the Start screen.