well i know you said no straps- I assume you refer to PowerGrip straps and not just to the straps that come on cages?
.....but I have to recommend PowerGrip straps anyway- I have them on both my road bikes (one a Rivendell Rambouillet). I use the MKS Touring pedals- they are a bit wide and that's good when I'm wearing my big insulated hiking boots in the winter.
Without the straps, my rough tread running shoes and hiking shoes slip right off the pedal despite all the pointy teeth and rubber tread- as soon as the bottoms of my shoes get wet as in walking on damp grass or mud.

You can adjust the straps LOOSE- just enough so your shoe can't slip forward off the pedal, but loose enough to easily slip your foot on and off the pedal.

I keep my straps snug though- I like them that way and it keeps my feet from creeping forward on the pedals too much without my realizing and then having unexpected toe overlap on a wobbly steep hill.

The Atlantis is a great bike! Not to mention gorgeous.