Spread the couscous on a large, deep plate and evenly pour salted water over it. Then rub between your fingers to separate the grains. Now put the plate with the couscous aside so that the semolina can absorb the water.
Heat half of the oil in the bottom of a steamer or in a large saucepan. Add the cleaned and chopped onions and carrots and cook for ten minutes over low heat. Add the spices and cook for another two to three minutes while stirring. Mix in the corn, zucchini and chickpeas, fill up with about a liter of water and add the tomato paste. Bring to the boil, then reduce the heat, just simmer the stew.
The couscous has now soaked up the water. Pour into the steamer or a metal sieve and loosen it up a little. Place the steamer or sieve over the vegetable stew, cover with a plate and steam the couscous for 25 to 30 minutes over a mild heat. Season to taste with salt and pepper.
Stir the remaining olive oil into the couscous and place this with the chickpea stew on a large, preheated platter. Garnish with coriander and serve immediately.