In a large bowl combine couscous and boiling water. Cover with plastic wrap and allow to steam for 5 minutes. Fluff couscous with a fork, breaking apart clumps with fingertips. Stir in currants, apricots, and pine nuts and set aside. In a small bowl whisk together the zest, juice, olive oil, salt, pepper and cayenne. Drizzle mixture over the couscous and toss to combine. Couscous can be made up to this point 1 to 2 days in advance. Store in an airtight container and refrigerate. Stir in the scallions. Transfer to a serving platter and garnish with mint.