Do you have a hardware raid? or a software assisted hardware raid(also called soft raid). manufacturors can be pretty deceptive about what they actually sold you in this space.
UEFI sees the first FAT partition and boots from it, and the configuration might simple mirror that partition on both disks. Just because a efi partition is seen don't prove you have raid it might simply be two mirrored filesystems.
On boot windows will load a driver and let the driver handle the raid ie it's software raid in all but name but windows don't always show this to the user. Linux tend to not ship soft raid drives in "the mainline tree" even when the manufacturers supply them because they have historically been problematic, and rarely actually provide benefits over the more optimized dmraid module.
Some vendors supply linux drivers for softraid controllers but it's one of the few exeptions where you actually need to go and download drivers on linux.
The typical difference here is that softraid controllers tend to depend on CPU offloading which makes them cheaper and usually slower then the full raid controllers you find in better server class hardware.