D.M.
Just some thoughts...
My son is now 32 months old and if I recall correctly, by that age he was chewing a variety of sized foods but, not with consistency. I made sure to teach by example, kids mimic what we do and that's how they learn. Even if you have to get funny about it and go overboard. If you already eat with your child all the time, then make it a big deal...say things like 'let's take a bite and chew our food'. I think being silly just goes with the territory.
I'm not sure how or what happens that clicks with a child that teaches them to chew, but I think it's a lot of trial and error and learning from watching. Don't make it a huge deal or stress about it, if he was in serious trouble he would have choked and since the vomit was from the food at the salad bar, I think you are okay.
If you have questions about his chewing or how to help him, you might want to ask his Pedi. I googled it and had a hard time finding anything.
good Luck!