Clean and prepare the squid, then cut it into bite-sized pieces.
Slice the tofu into 2cm thick pieces and remove excess moisture.
Add oil to a pan and stir-fry the squid and tofu over high heat.
Slice and add the onion, green onion, and garlic; stir-fry together.
Season with soy sauce, red pepper powder, sesame oil, and pepper.
Continue stir-frying until all ingredients are cooked thoroughly.