Place octopus in pressure cooker and cover with water. Add onion, garlic, fennel fronds, oregano, and bay leaves. Close and lock lid. Set pressure cooker to "fish", adjust time to 15 minutes, and press "start/stop".
When done, natural release for 10 minutes, then do a quick release to make sure all pressure is released before opening lid. Carefully open lid and allow octopus to cool down in pot.
When cooled, remove octopus. Cut tentacles into 2-inch pieces. Drizzle octopus with oil and top with paprika. Serve with lemon wedges and a salad.