1. Preheat a gas grill to medium. Oil grates; grill peppers, turning once or twice, until charred, 10 to 15 minutes. Transfer to a bowl; cover tightly. Let stand 10 minutes. Remove from bowl; scrape away skin.
2. Brush corn with 1 Tbsp. olive oil; season with salt and pepper. Grill corn, turning, until lightly charred, 7 to 10 minutes. Remove from heat and cool.
3. In a large bowl, whisk vinegar and mustard. Season with salt and pepper and whisk in remaining olive oil. Dice peppers; cut corn kernels from cobs. Mix peppers, corn, scallions and cilantro in bowl with dressing and toss. Season with salt and pepper. Serve at room temperature.
This recipe has also been published as: Grilled Corn and Pepper Salad