Hi i am looking for specs to support 10g internet. No vpn, just 100 vlans with dhcp and nat.

Does anyone know if the RouterOS works on this hardware with 32Gb of RAM?
Supermicro SuperServer 5018D-FN8T Xeon D Mini 1U Rackmount,10GbE LAN, SFP+, IPMI

I am also looking to add another 10G fiber card, any recommendations?

Thanks

It really depends on LAN it uses. Look for some recent topics on Intel card support in ROS 7. There is a good chance these will be supported soon.