In the past, I've had two Haibikes and it was very easy to fix a flat on the road.  Just carry the usual spare tube, tire levers, and a pump/co2.  No problem.
However, my new e-bike comes with the Alex Rims and Shwalbe Big Ben Plus tires.  I've seen this combo on other e-bikes as well.  These appear to be European and the parts are difficult to find in the U.S. (e.g. 20" presta tubes).  Yesterday I had a flat when I got home and I couldn't unseat the bead from the tire.  First time I've ever encountered such a difficult tire.  After many attempts and Google search for help, I had to take it to my local bike shop.  They had a heck of a time as well.  It eventually took two techs pulling on it at the same time to unseat the bead.  I'm now learning others are having a hard time with the Alex wheel/Big Ben combo. 
Problem is that I HAVE to be able to fix a flat on the side of the road.  Some of my rides are 20+ miles away from home.  With my current wheels/tires, I cannot do that.  Anyone else experienced this?  Is this because heavy duty bikes (such as cargo/utility) bikes need beefier wheels/tires and you just can't change them roadside? 
I'm thinking about purchasing new wheels/tires even though my new bike is only one day old.  It is an absolute MUST that I be able to fix a flat on the road.  And what combination would you recommend?  My rear tire is 26" (10 speed cassette w/quick release) and my front tire is 20" (2.15" wide tire).  And they're both presta.  I would prefer Shrader since it's much more common in the U.S. (for those sizes).