Heat large skillet over medium heat with ½ tsp vegetable oil, add shrimp and squid rings, season with salt and pepper. Cook about 2-3 minutes until shrimp are pink and rings are tender.
In large bowl, mix in diced tomatoes, onion Worcestershire Sauce, hot sauce, tomato paste, cayenne pepper, cumin, chili powder and salt. Cover and refridgerate 30 minuts.
Once shrimp and squid have cooled down, chop into small pieces and then add to tomato misture and add lime juice and cilantro. Refrigerate another 1-2 hours before serving.
Serve on tostadas or tortilla chips.