Heat the vegetable oil in a large heavy-based saucepan to 180°C.
Mix the cooked rice with the soy sauce, sesame oil and spring onions in a mixing bowl; it should be sticky. Shape into 6-7cm patties and dust in the flour, shaking off any excess.
Dip in the egg and roll gently in the breadcrumbs. Deep-fry, in batches if necessary, for 3-4 minutes until golden and crispy on the outside.
Drain on kitchen paper then arrange in a serving bowl. Garnish with the long slices of spring onion and serve immediately.