Pour hot salted water over couscous and allow to swell for 5 minutes. When all the liquid is absorbed, loosen with a fork.
Dice the tomatoes. Cut onion into thin slices, chop garlic coarsely, crumble feta cheese, chop mint coarsely (set aside a few leaves for garnish).
For the marinade, mix vinegar with coriander, salt, pepper and oil. Mix the diced tomatoes, onion slices and garlic into the marinade and add the couscous.
Loosely fold in cheese, mint and nuts.
Let the salad stand and serve garnished with cress.