Cannot get more than 29.88 Hertz refresh rate from 2016 MacBook Pro and Acer XR342CK monitor
As it turns out, the Acer XR342CK monitor is not compatible with the 2016 MacBook Pro 13" (and possibly 15", I haven't tried). I talked to two different Acer support techs and they both told me there is a compatibility problem between the laptop and monitor.

To verify this information, I was able to get the monitor to connect with the same cables I was using to a Mac Pro tower with an NVIDIA GTX 980 and it worked flawlessly and reached 75 Hertz by default.

I have purchased and tested two of these monitors and they both displayed the same problem with connectivity and refresh rate (and caused my MacBook to hang/reboot). Both of these monitors also have terrible image persistence/burn-in/echo, something to keep in mind if you are considering one of these monitors for your setup.

I sure wish Apple would make a curved display.