In a small saucepan, bring 1/2 cup water to a boil. Remove from heat. Stir in 1/2 cup couscous; season with coarse salt and freshly ground pepper. Cover and, off heat, let steam in the pan, 5 minutes. Add 2 thinly sliced scallions, 1/4 cup fresh mint leaves. 1 1/2 teaspoons extra-virgin olive oil, and 1 1/2 teaspoons fresh lime juice; fluff couscous with a fork, and serve.