Prep the fish cake and vegetables: Cut the fish cake sheets into thin strips or bite-sized pieces. Set aside. Thinly slice the carrot, slice the onion and roughly chop up the green onions.
Pan-fry the vegetables: Heat a little oil in a pan over medium heat. Add the carrots, onions and green onions. Stir-fry until the vegetables are soft and slightly fragrant, about 4 minutes.
Add the fish cake: Toss the fish cake into the pan and stir-fry with the vegetables for about 1 minute so it warms through and starts to soak up some flavor.
Make the sauce: In a small bowl, mix together the soy sauce, sugar, sesame oil and water until combined.
Combine everything: Pour the sauce over the vegetables and fish cake in the pan. Stir well to coat everything evenly.
Thicken the sauce: Let the mixture cook for another 1 minute, stirring occasionally, until the sauce is slightly thickened and glossy.
Finish and serve: Sprinkle with sesame seeds and give it a final toss. Serve hot as a side dish, or enjoy it with a bowl of rice!