Put the couscous in a bowl and add the boiling water.
Stir in 2 teaspoons of salt, cover tightly with plastic wrap and let stand, stirring once, until the grains are plump and tender.
Meanwhile, heat the olive oil in a medium skillet. Add the corn, onion, coriander and caraway and cook over moderately low heat, stirring, until the onion is softened, about 8 minutes. Transfer to a large bowl and let cool.
Add the couscous to the bowl, along with the bell pepper, jalapeños, scallions and mint. In a bowl, whisk together the lime juice, canola oil, vinegar, honey and lime zest. Add to the couscous and toss. Season with salt and pepper and serve.