Soak the soybeans in water for at least 8 hours.
Boil the soaked soybeans in boiling water for 5 minutes, then rinse them in cold water.
Blend the boiled soybeans with water until smooth to make the soybean soup base.
Season the soybean soup with salt to taste.
Cook the somyeon noodles and rinse them under cold water to prepare.
Place the noodles in a bowl and pour the soybean soup over them.
Top with sliced cucumber, tomato, or your preferred garnishes.