Construct your pair.
Newer version of Outfield Appolos features soft breathable pads on the heel and the rise of the foot and softened element that goes through finger.
The second generation of the Apollo model has fixation of all fingers.
Technological details will open you large scope for creativity. In order to turn sandals into flip flops, just push the slingback to the upper-front, it can even be done without hands. The slingback and the elastic with fastex on the ankle are removable, so you can also take them off easily.