Please read the installation manual. The insulation pad is for separating the backplate and motherboard to prevent shorting.
It's not the same as a thermal pad and insulation is the opposite of what thermal pads / paste do.
You might be able to run the system with no thermal paste and just dry mount the cooler onto the cpu for a windows installation but the pump and fans might have to run at pretty high rpm to keep temps in check. Make sure there isn't any auto-oc'ing or enhanced turbo from the motherboard settings if you decide to do this.