Put the quinoa in a saucepan and add twice as much cold water to it and a pinch of salt. Bring to boil and simmer for about 15 minutes. When the water is completely absorbed and the grains are soft, but not mushy, turn off the heat. Loosen the grains with a fork, add the oil and the lime juice. Rest under cover.
Blanch the pea in boiling water for 3 minutes, then rinse under cold water and drain.
Slice the radishes and spring onions. Peel the avocado, chop the flesh roughly.
Drain chickpeas.
Shred the fish into chunks, using your fingers (remove the skin first).
Mix the yoghurt with horseradish and herbs.
In a mixing bowl, combine the peas, quinoa, chick peas, radishes and spring onions. Gently fold in the fish pieces. Season with salt and pepper.
Serve with the spiced yoghurt dressing.