For sauce, in a food processor bowl or blender container, combine the undrained tomatoes, green pepper, the quartered onion, green chili peppers, chili powder, paprika, salt, cumin, ground red pepper, and garlic powder. Cover and process until nearly smooth. Transfer to a large saucepan.
Bring sauce to boiling. Reduce heat. Cover and simmer for 30 minutes. Cool, if desired. *
For sandwiches, in a medium saucepan, combine 1 cup of the sauce and the frankfurters. Heat through. (Store the remaining sauce in a covered container in the refrigerator for up to 4 days.) Serve franks on buns with chopped onion, mustard and sauce. Makes 4 servings.
Prepare and cool the sauce as directed. Freeze in a freezer container for up to 3 months.