Blanch Watercress in salted boiling water very quickly. Basically you put the Watercress into the boiling water root side first and as soon as whole of them went into the water, remove. Dip in cold water to stop cooking further, drain well and squeeze to remove excess water. They should be still crunchy.

Cut into 5cm in length. Add drained Tuna, finely sliced Red Onion, and all other ingredients and mix well.