Cut off the root end of the enoki mushrooms and trim them into bite-sized pieces.
Slice the onion thinly and chop the green onion.
Heat cooking oil in a pan and stir-fry the onion and green onion.
Add the enoki mushrooms and stir-fry together.
Season with soy sauce, sugar, minced garlic, and pepper.
If needed, add a little water and bring to a simmer.
Place the stir-fried enoki mushrooms on top of rice.
Finish with a drizzle of sesame oil and a sprinkle of sesame seeds.