FileUtil.DeleteFileOrDirectory  

static function DeleteFileOrDirectory (path : String) : boolean

Description

Deletes a file or a directory given a path.

This function's path is relative to the project root folder but it can also accept absolute paths.

All file separators should be forward ones "/" (Unix style).

// creates a menu entry to remove a file or a directory.
@MenuItem ("Example/Remove Something")
static function RemoveAFile () {
    //removes the file
    FileUtil.DeleteFileOrDirectory("your/path/to/the/folder/or/file");
}