Heat a small saucepan over medium-high heat. Add oil to pan, swirling to coat. Add shallots; sauté 2 minutes or until tender. Stir in couscous; sauté 1 minute. Add tomatoes, broth, and corn; bring to a boil. Cover, remove from heat, and let stand 5 minutes. Fluff with a fork. Stir in lime juice and cilantro.