Let’s assume it’s actually what is known as street food back in South Korea. There are some really great things you can get, and of course some odd ones. My favorite is 토스트 (“Toast”) which is Korea’s take on grilled cheese sandwiches. There’s a lot to be said for a toasted sandwich made with spicy jam, lettuce, pickles, cheese, and a hard-fried egg. Of course you non-vegetarian types can go for the ones with spam, ham, or even steak.
Then there’s 호뗙 (“Ho-ddeok”) which is a sweet pancake.
Another one I quite like is 잉어빵 (“Eeng-eo-bbang”), which is a hot pastry shaped like a fish and filled with either red bean paste or custard. Waffles are quite popular at street stalls in Korea, too. You can get those with icing or jam as toppings.
You may enjoy 오뗑 (“O-ddeng”), which is various fish cakes boiled in water and served up on a stick. You pick out the ones you like with your own kebab stick. My wife quite likes those. AFAIK, it’s actually Japanese but still popular in Korea.
This one’s also actually Japanese and popular in Korea: 타코야기 (“Ta-ko Ya-ki”), “tako” being the Japanese word for octopus. It’s a pastry ball filled with some paste and diced octupus.
떡볶이 (“Ddeok-bokk-ee”, spicy rice cakes) are extremely popular. For those not initiated into Korean cuisine, when the locals say something is spicy, they are not fooling around! It’s various shaped rice cakes slathered in Korea’s spicy sauce.
계란빵 (“Gye-ran-bbang”, egg bread) is something I was introduced to within the last few years. It’s a regular bread roll cooked aroundd a boiled egg (minus the shell, of course).
김밥 (“Gim-bap”, seaweed rice) is good and you can have it made-to-order. I get mine without the imitation crab meat and without the tuna, ham, and/or spam that is so popular in Korea. An interesting twist on this is 누드김밥 (“Nu-deu Gim-bap”, nude seaweed rice), which is not served by naked wait-staff, but rather is simply the gim-bap rolled backwards with the rice on the outside. Another note: gim-bap absolutely is not “Korean sushi”; there’s no raw fish in it.
참외 (“Cham-oi”, yellow melon) is absolutely delicious, IMHO! The first time a friend tried those, we almost missed the last bus back to our town because he could not stop eating the things.
One thing I find rather disgusting (and so does my wife, who is Korean) is 번데기 (“beon-de-gi”, silkworm pupae). It’s boiled, not raw, so you adventuresome types might want to give it a go.
There are other things usually depending on where you are. Each locale (city, neighborhood) has their own take on a lot of these. Also if you happen to know Korean Sign Language, you might make the waffle-stall’s operator’s day since quite a lot of those are operated by the Deaf.
Now I’m hungry and it’s not even close to lunchtime here!