We are currently working on a way to make this more accessible for keyboard users.
Right now, if you have a missile weapon equipped and appropriate ammunition (arrows for long- and shortbows, bolts for large and hand crossbows, rocks for slings), you can simply click on a distant enemy. Hovering over them will indicate a flight path and highlight any obstacles.
Making this more accessible to keyboard- and gamepad user is a priority for the next update.