Prep a court bouillon: Fill a 2-quart pan about ⅔ full with cold water. Just enough to submerge all of the octopi you're going to poach.
Roughly chop shallot, carrot, celery and add to water. Cut lemon in half, squeeze, and add to water.
Next, add bay leaf, salt, and peppercorns.
Bring water to a boil and lower a simmer. Continue simmering, covered, for 15 to 20 minutes.
Reduce heat to low so that only a few bubbles break the surface.
Add the cleaned octopus to the simmering court bouillon and cover, cooking for approximately 40 minutes. The octopus will be done when the tip of a sharp knife can be inserted into the underside.
Once octopus is poached, drizzle with olive oil, salt and pepper and set aside. Make Vinaigrette
Once octopus is marinated in olive oil, place on a grill to get a nice char, about 2-3 minutes on each side
Slice octopus into bite sized pieces.