Put the glass noodles in a bowl and pour boiling water over it. Let the noodles soak for 1 minute. Drain and cut into 2 cm pieces. Leave aside.
In a bowl, beat the eggs with 1 tsp fish sauce. Add the spring onions and glass noodles and leave until needed.
In a pan on medium high, add 1/2 tbsp of oil and cook the brown onions until beginning to colour. Add the pork mince, salt and pepper and cook for roughly 2 - 3 minutes.
Once the mince is cooked, add it to the beaten eggs and gently mix.
In a fry pan on medium high, add 1 tbsp of oil and pour the egg mixture into the center. Shake the fry pan so that the egg mixture runs all the way to the edges of the pan. Use a spatula to even out the omelette.
Let the omelette cook for 2.5 minutes. Then tilt the fry pan forward so that the omelette slides all the way to the edge. To the side of the omelette that is closest to you, slide the spatula underneath. Use the pan to flip the omelette and the spatula to control it.
Cook for a further 2 minutes and then serve with rice.