Four finger swipe left/right -> Task switcher shows up (a horizontal bar with app symbols).
Two finger swipe -> highlights an icon and shows app name.
?? -> switches to highlighted app. Since the highlighting is independent of the mouse cursor, a click doesn't work here without moving the mouse cursor. But I don't want this (locate mouse cursor, move the extra mile..).
Maybe Better Touch Tool allows to configure a click to act as SPACE or RETURN in the task switcher? But how did Apple intend to use this?