Remove Project from Android Studio

File > Close Project

move your mouse cursor on the project and press Delete keyboard button :)

EDIT try this solution, works for me

You must close the project, hover over the project in the welcome screen, then press the delete button.

In the "Welcome to Android Studio" opening dialog you can highlight the app you want to remove from Android Studio and hit delete on your keyboard.

This is for Android Studio 1.0.2(Windows7). Right click on the project on project bar and delete.

Then remove the project folder from within your user folder under 'AndroidStudioProject' using Windows explorer.

Close the studio and relaunch you will presented with welcome screen. Click on deleted project from left side pane then select the option to remove from the list. Done!