Bring 475ml water and quinoa to the boil in a saucepan. Reduce heat to medium-low, cover, and simmer until quinoa is tender, 15 to 20 minutes.
Bring 350ml water to the boil in a saucepan; remove from heat and stir couscous into the water. Cover saucepan and let stand until water is absorbed completely, about 10 minutes. Fluff couscous with a fork.
Combine quinoa, couscous, chickpeas, tomatoes, red peppers, celery, cranberries, pecans, shallots, parsley and fresh coriander.
Combine lemon juice, curry paste, soy sauce, sugar, sesame oil, cumin and salt in a blender; blend until smooth. Slowly pour olive oil into the blender while it is still running until dressing is emulsified. Pour dressing over quinoa-couscous mixture and toss to coat.