For the couscous salad, first put the couscous in a bowl. Mix the young onion rings with the couscous and knead lightly so that the couscous absorbs the onion flavor. Add the hot water and let swell for 20 minutes.
Mix a marinade of parsley, lemon juice and olive oil. Season with sea salt and pepper and mix well with the couscous.
Dice the tomato and stir into the couscous salad.