when you say "disc" there are two potential meanings.

if you mean disc brakes then yes, it's quite easy. you can just run a single cog on a multispeed (disc compatible) freehub along with a lot of spacers. this is how a lot of ss mountain bikers do it.

i've also seen an adaptor that screws onto the opposite side of a flip flop hub that has attachments for a disc rotor. kind of a neat idea, but i have no idea how well they work and i forget who makes them.

they also make singlespeed specific disc brake hubs, so that's another option but in general you're gonna pay more for the equivalent quality and weight of a multispeed hub.

if you're asking about disc wheels:


some can be ss, some can't, but i'm really not the guy to answer that question.