Peel and finely dice the onion and garlic. Heat 1 tablespoon of oil in a saucepan. Sauté onion and garlic in it. Add stock and 2 tbsp. oil. Stir in couscous, remove from heat and let it swell for about 5 minutes.
In the meantime wash, clean and chop the tomatoes. Halve the olives. Wash parsley and dab dry. Pluck off the leaves and cut them a little smaller. Cut cheese into pieces. Clean and wash the spinach.
Season vinegar with salt, pepper and sugar. Stir in 2 tablespoons of oil drop by drop. Loosen the couscous with a fork, season with cumin and cayenne pepper. Mix couscous, cheese, tomatoes, parsley, olives, spinach and dressing.
Arrange salad on plates.