Chicken Tikka Kebabs with Charred Tomato Chutney and Warm Flat Bread

Name: Chicken Tikka Kebabs with Charred Tomato Chutney and Warm Flat Bread
Ingredients: 1 cup plain yogurt; 1 rounded tablespoon mild curry paste; 1 lemon, juiced; A handful (3 tablespoons) cilantro leaves, finely chopped; 2 pounds boneless, skinless chicken breast meat, cut into 1 1/2-inch cubes; 3 plum tomatoes; 1/2 cup tomato sauce or tomato puree; 1 teaspoon mustard seed; 1 teaspoon coriander seed; 1/2 teaspoon crushed red pepper flakes; Coarse salt; Packaged flat breads, sold near packages pita bread in market; 2 pounds white-skinned potatoes, peeled and diced into small cubes; 1 teaspoon cumin seeds; 2 tablespoons (2 turns around the pan) peanut or vegetable oil; 1 small sweet onion, chopped