Heat 2 tablespoons of oil in a large saucepan on high. Cook vegetables, stirring, for 5 minutes. Add 1 cup water and simmer, covered, for 10 minutes, until just tender. Remove lid and cook for another 5 minutes, until liquid evaporates and thickens slightly.
Meanwhile, heat remaining oil in a saucepan on medium. Cook cumin for 1 minute, until fragrant. Add 1 cup water and season to taste. Remove from heat, stir in couscous and set aside, covered, for 5 minutes. Fluff up with a fork and season to taste.
Top couscous with vegetables, drizzle with pan juices and season to serve.