Yes, you can partition your SSD as you want, but you will not get any performance increase by RAIDing them back together (which is probably not possible anyway).
A RAID normally consists of two or more different HDDs or SSDs, not partitions, and a RAID 0 is getting a speed advantage via striping the data onto both disks and thus spreading the load and thus getting almost the most speed of either device thus almost doubling the speed.
If yo use one device with two partitions and want to RAID those two partitions, the load is still only on one device and there is no speed gain.
Is that understandable?