Put the noodles in a large bowl and fill it with cold water. Set aside.
Make the soup broth. Put the first 8 ingredients from the broth ingredients into a food processor. Pulse until smooth. Pour it into a medium size pot, add the chicken broth, carrots and coconut milk. Simmer on medium until the carrots are tender.
Season the salmon fillets with salt and pepper. Prepare a non-stick pan on medium-high heat. Put a teaspoon of oil and fry the fish until it is cooked and flakes off easily with a fork.
In a small pot filled with water, portion out the vermicelli per person. Once the water boils put the noodles and watercress and cook for no more than 30 seconds. Drain and put in bowls, top off with the salmon and soup broth. Garnish with coriander (optional). Enjoy