Bring a large pot of water to a boil with the bay leaf and salt.
Dip the octopus into the boiling water three times, about 10 seconds each, before fully submerging it.
Simmer gently for 35–40 minutes, until fork-tender.
Remove the octopus, let it cool, then slice into ¼-inch rounds.
Blend the mayonnaise, olives, olive oil, lime juice, and black pepper into a smooth, dark purple-black sauce.
Arrange the octopus slices on a platter and spoon the olive sauce generously over the top.
Chill for 10 minutes before serving.