Grilled Chicken with Tomato-Avocado Salad

INGREDIENTS

• 1/4 cup nonfat buttermilk
• 3 tablespoons canola mayonnaise
• 2 tablespoons minced fresh flat-leaf parsley
• 1 tablespoon minced shallots
• 1 teaspoon minced fresh thyme
• 1 teaspoon cider vinegar
• 1/4 teaspoon freshly ground black pepper
• 1/8 teaspoon kosher salt
• 1 garlic clove, minced
• 4 (6-ounce) skinless, boneless chicken breast halves
• Cooking spray
• 1 1/2 tablespoons olive oil
• 1 teaspoon onion powder
• 3/4 teaspoon ground cumin
• 3/4 teaspoon kosher salt, divided
• 1/4 teaspoon chipotle chile powder
• 2 ears yellow corn, shucked
• 1 small red onion, cut into 1/2-inch slices
• 2 yellow tomatoes, each cut into 4 slices
• 2 red tomatoes, each cut into 4 slices
• 1 cup cherry tomatoes, halved
• 1 sliced peeled ripe avocado