There aren't a lot of guide out there (that I found) that show you how to do this w/o gpart. SmartOS has only basic software on it and parted wasn't one of them.
Here is how I did it:
format fdisk #push 3 (multiple times) to delete partitions #push 1 to create partitions, use UNIX type #push 2 to make none of them "active" #push 6 to write changes
I created 2 UNIX partitions on my c1t2d0 device. My first partition is c1t2d0p1, the second is c1t2d0p2.
You can use this in ZFS like:
zpool create poolname c1t2d0p1
I don't know if UNIX partitions are the "best", but it seems to work.
I used this so I could partition my SSD as ZIL (log on first partition) and local backup (it doesn't get used very much and doesn't slow down my zil).
extra: If you want to "split" the drive instead of partition, check out this reference. It talks about p1 vs s1 vs n1 (at the end of a device).