For the Octopus:
One 5-to-6-pound whole octopus
2 teaspoons habanero oil
¼ cup fresh lime juice
Kosher salt, to taste
For the Charred Habanero Oil:
8 habanero chile peppers, stemmed
½ cup olive oil
For the Aguachile:
½ (1½ cups) large white onion, very thinly sliced
¾ cup fresh lime juice, divided
Kosher salt, to taste
4 medium Persian cucumbers, cut into ¼-inch-wide half moons
4 tablespoons habanero oil
2 avocados, pitted and quartered
2 tablespoons olive oil
1 cup loosely packed cilantro, for garnish
Flakey sea salt (such as Maldon), for serving
Fresh lime juice, for serving
Olive oil, for serving
1. Make the octopus: In a large pot, cover the octopus completely with cold water by 2 inches. Bring to a boil over high heat. Lower the heat to a simmer and cook for 1 hour, uncovered. Turn the heat off and let the octopus rest in the cooking liquid for 1 hour, until tender.
2. Meanwhile, make the charred habanero oil: Place the habaneros on a sheet tray and using a kitchen torch, heat the chiles until they are black and blistered all over. Alternatively, adjust the oven rack to the upper position and turn on the broiler. Place the peppers on a foil-lined baking sheet. Broil the habaneros, rotating the baking sheet every 2 minutes, until well charred, 4 to 6 minutes. Remove and set aside.
3. In a blender, blend the charred habaneros and olive oil until smooth. Stop to scrape down the sides of the blender as necessary. Makes ½ cup. Make ahead: Habanero oil can be made up to 1 week ahead. Cover and chill.
4. Remove the octopus and transfer it to a paper towel-lined rimmed baking sheet and allow it to drain for 10 minutes. Using a sharp knife, separate the tentacles and discard the head. Thinly slice the tentacles into ¼-inch round pieces. Place them in a large mixing bowl and toss with 2 teaspoons of habanero oil and ¼ cup of lime juice. Season with salt and set aside.
5. Make the aguachile: In a small mixing bowl, combine the onions with 2 teaspoons of the lime juice. Season with salt and allow to macerate for 10 to 15 minutes.
6. In a separate mixing bowl, combine the cucumber with ¼ cup lime juice and 4 teaspoons of the habanero oil. Season with salt and marinate for 10 to 15 minutes.
7. Using a paring knife, carefully remove the peel from the avocado. Place the avocado on a sheet tray and using a kitchen torch, heat the avocado until blackened (it should resemble avocado skin). Cut each quarter into eighths and place in a mixing bowl. Toss the avocado with 2 tablespoons of olive oil and 2 tablespoons of lime juice. Season with salt.
8. Mix the octopus with the cucumbers and transfer to a serving platter. Top with the avocado, macerated onions and cilantro. Garnish with Maldon salt, an extra squeeze of lime and an extra drizzle of olive oil, and serve.