Heat oven to 400° F. Place the ribs in a roasting pan or on a baking sheet in one layer. In a bowl, combine the chopped garlic, oregano, cayenne, 1 tablespoon of the oil and 1/2 teaspoon salt and mix well. Cover both sides of the ribs with the garlic and oregano mixture, coating evenly. Roast, flipping once, until tender, about 1 hour. Let cool, then shred the meat, discarding the bones.
Meanwhile, make Green Olive Pesto: in a food processor, combine the garlic cloves, green olives, parsley, and basil. With the motor running, slowly add the remaining 1/4 cup olive oil and process until the oil is fully incorporated.
Slice each baguette piece in half horizontally. Spread one side of a baguette half with some Green Olive Pesto and layer on some arugula and black olives. Top with some shredded pork and place the other baguette half on top.