Using rubber gloves, remove and discard stems and seeds from chile peppers. Wash chiles in cold water; drain. Tear chiles into strips; place in a small bowl. Add hot water; let stand 20 minutes.
Pour chile mixture into container of an electric blender; cover and process until smooth, stopping once to scrape down sides. Set mixture aside.
Combine flour and next 5 ingredients in a small bowl; set aside.
Cook onion and garlic in oil in a small skillet over medium-high heat, stirring constantly, 5 minutes or until onion is tender. Add flour mixture; stir well. (Mixture will be dry.) Cook, stirring constantly, 1 minute. Gradually add chile mixture; cook over medium heat, stirring constantly, until mixture is thickened and bubbly. Stir in tomato paste and salt. Let cool slightly.
Pour mixture into container of electric blender; cover and process until smooth, stopping once to scrape down sides. Stir in lime juice. Store in refrigerator. Serve as a condiment with couscous, soups, or stews, or spread on bread.