Preheat broiler to high. Place chiles, tomatoes, shallots, and garlic cloves on a baking sheet. Broil vegetable mixture for 10 minutes or until charred, turning once after 5 minutes. Remove chiles from pan. Place in a paper bag; fold to close tightly. Let stand 15 minutes. Remove skins, tops, and seeds from chiles; discard. Remove skins from garlic; discard. Place chiles, garlic, tomatoes, shallots, cilantro, lime juice, and kosher salt in the bowl of a food processor; pulse 10 times or until mixture is well combined.