Well you wouldn't put simple HTML pages into the WEB-INF/views folder I guess, but instead somewhere at the top of your .war file structure. Then you can simply address it with a relative path (to your context path). That's what I would do probably.
If you really want to put it into the WEB-INF/views folder too, I suppose you need to go through a command to display the page, as you can't access pages under WEB-INF directly. In this case your command can do a context.forward("/WEB-INF/views/.../mypage.html").