As MidgetMage stated most oUF layouts (and oUF itself) do not have /commands. All configuration and tweaking is done via lua.
That said, there are now two layouts that have in-game configs:
I would suspect others will be coming with in-game config menus as authors take advantage of the various pre-built config libs such as Portfolio, Ace3 (AceConfig), and others. oUF itself will not come with a in-game config menu as it's the framework on which layouts are built, in-game menus will be supplied with the layouts.