Finely grind coriander seeds in an electric coffee/spice grinder or with a mortar and pestle.
Bring water, 2 tablespoons oil, and salt to a boil in a 1 1/2 to 2-quart heavy saucepan. Stir in couscous and coriander seeds, then cover pan and remove from heat. Let stand 5 minutes.
Fluff couscous with a fork and stir in remaining tablespoon oil, apricots, parsley, and salt and pepper, to taste.