1.Remove the octopus tentacles from the package, rinse and place them on paper towels to dry. Heat up the grill or a grill pan then drizzle 1 tablespoon olive oil on the octopus and season with salt and pepper on both sides.
2.Grill on both sides for a few minutes until you see grill marks then transfer to a cutting board. Cut the octopus into bite-size pieces. Place them in a glass or ceramic salad bowl.
3.Add tomatoes, olives, garlic, parsley, 1/2 teaspoon salt, 1/4 teaspoon pepper, oregano, lemon juice and 3 tablespoons olive oil. Gently toss to coat.
4.Cover and let the salad rest at room temperature for 20 minutes to allow the flavors to meld. Mix again and serve.