Have you tried Kong-guksu(noodles in cold soybean soup)? This is a very popular dish, especially in summer.
Kong means soybean and guksu mean noodle. The soup is made from grounded soybean. If you make this from scratch, it takes a lot of time! But I found this convenient product “soybean powder” on Singsing Mart. You should mix the powder and water (I added ice cubes to make it very cold!) well. Then add the cooked noodles. You also need to add salt. The powder itself doesn’t have saltiness at all. I recommend adding adequate salt. If tastes slightly bland, it doesn’t taste good. In addition, you may add kimchi to the noodles. It makes the soup extremely delicious. My favorite summertime noodle! Please try it!!!