In a 5-qt. slow cooker, combine the first 7 ingredients; stir in 2 cups peaches. Cook, covered, on low 3-4 hours or until onion is tender., Stir tomato paste and remaining peaches into slow cooker. Cool. Transfer to covered containers. (If freezing, use freezer-safe containers and fill to within 1/2 in. of tops.) Refrigerate up to 1 week or freeze up to 12 months. Thaw frozen salsa in refrigerator before serving.