Easiest way (in my opinion) - drag (from explorer/finder) and drop on library grid (which opens import dialog box). You still have to review settings (and maybe choose an import preset), but at least the photos you want to "open" (import) will already be checked and ready to go..
As David already explained, it can't be the same as Photoshop, since you're not "opening" so much as cataloging, and Lr needs to know how you want things done.., for example folder/file naming, backup, format conversion, ...
I mean, if you just want to add in place and nothing else, then setup a "Just Add In Place And Nothing Else" import preset and use it when importing in that fashion..
Don't get me wrong - I'm not saying there isn't some streamlining/optimizing that could be done, but once you learn what to do, you just do it..
