Heat the 2 teaspoons oil in a large frying pan and cook and stir onion until soft. Remove from the heat, stir in couscous and pour in boiling water. Add salt, cover and let sit for 10 minutes until water is absorbed.
Fluff the couscous with a fork and transfer to a big salad bowl. Add carrots, cucumber, red pepper and chick peas und mix well.
In a small bowl whisk together olive oil, vinegar, soy sauce, sugar and curry powder. Pour dressing over couscous and stir until well combined. Add lemon juice, salt and pepper to taste and serve.