For now, You can't. But we will try to update our software to allow this as soon as possible. For now, you can only uninstall whole application or delete a game from your disk cache manually. The games are located in a following paths:
C:\Documents and Settings\[User Name]\Application Data\AppClient\Packages\ (WinXP/2000)
C:\Users\[User Name]\Application Data\AppClient\Packages\ (WinVista/7)