Slice onion, zucchini, shiitake mushrooms, green onion, and bok choy into bite-sized pieces.
Rinse the squid and shrimp thoroughly and drain well.
Add olive oil to a pan and sauté green onion and garlic to bring out the aroma.
Add the squid and shrimp, then stir-fry quickly over high heat.
Add the prepared vegetables and stir-fry together.
Sprinkle in the chili powder and keep stirring so it doesn't burn.
Pour in water (or low-sodium seafood broth) and bring to a boil.
Season with soup soy sauce, salt, and pepper to taste.
Place rice in a bowl, pour the cooked jjamppong soup over it, and serve.