Boil pasta; reserve 1/2 cup cooking water before draining. Meanwhile, heat oil in a large nonstick skillet. Add onion, saute 10 minutes or until golden and tender. Add marinara sauce and raisins, bring to a simmer. Stir in tuna and olives, heat through. Toss pasta, sauce and reserved cooking water to mix and coat.
498 cal, 21 g pro, 81 g car, 6 g fiber, 9 g fat (2 sat), 20 mg chol, 795 mg sod