In a frying pan over medium heat, heat sesame oil and lightly fry the onions, celery and beansprouts. Stir in cornflour and add prawns, soy sauce and salt. Stir until well blended. Remove from heat and transfer to a bowl.
Return the pan to the heat, and add the beaten eggs. Fry the eggs while stirring gently. Return the vegetable and prawns mixture to the pan while the eggs are still liquid. Finish frying until eggs are fully cooked.