Cut the squid bodies along the sides to open flat. With a thin sharp knife, lightly score the insides, being careful not to cut through all the way.
In a bowl, combine 2 tablespoons of the olive oil, lemon juice, oregano, garlic, salt, and red pepper flakes. Add the squid bodies and tentacles, toss to coat, and marinate for 2 hours, refrigerated, turning twice.
Preheat the grill to high heat.
Cook potatoes in boiling salted water until tender. Drain and set aside.
With a pastry brush, lightly coat both sides of the sliced bread with the remaining 2 tablespoons olive oil. Place the bread on the hot grill and cook until golden brown on both sides, 2 to 4 minutes. Arrange on a large platter.
Grill the squid, turning until opaque, slightly golden, and just cooked through, about 2 to 3 minutes. Remove the squid to a cutting board and slice into strips. Slice the tentacles if desired.
Place the squid on top of the grilled bread and top with the chopped olives. Arrange potatoes decoratively around squid. Lightly drizzle with additional extra virgin olive oil as desired, sprinkle with Essence and parsley, and serve with the lemon wedges on the side.
Emeril's ESSENCE Creole Seasoning (also referred to as Bayou Blast):
Combine all ingredients thoroughly.
Recipe from "New New Orleans Cooking", by Emeril Lagasse and Jessie Tirsch. Published by William and Morrow, 1993.