Blac Chyna's new mystery man sucks her toes at dinner !!!

Blac Chyna has a new boo in her life, and the guy seems to have an appetite for bunions and toenails -- 'cause that's what he had for dinner, or maybe just dessert.

BC was out Sunday night in Woodland Hills, CA -- where she and her mystery man walked up to a restaurant together, apparently in couple mode. And, if their joint appearance didn't give it away, well ... what he did next certainly does.

The guy started snackin' on her foot right there at the table!!! Some thing's just ain't gonna be on the menu ... know what we're saying?

Of course, to each his own (shout-out to foot fetish fans), but there's a time and place to lick up some toe jam -- and AT the dinner table probably isn't it.

GROSS!!!!