Attach an Anova Precision Cooker to a vessel of water and set the temperature to 170.5°F (77°C).

Remove the head and slice the octopus tentacles in half, then transfer to a large bowl. Add 3 tablespoons of the olive oil and 1 tablespoon of the salt. Stir to thoroughly coat. Divide between vacuum-seal bags, adding 2 cloves of garlic and 1 bay leaf per bag. Seal.

Transfer to the water bath and cook sous vide the octopus for 5 hours. Transfer to an ice bath to cool, then refrigerate overnight.

To make the white bean puree, heat 2 tablespoons of the oil in a large skillet. While the oil is heating, finely chop the remaining 2 cloves of garlic. When the oil is shimmering, add the garlic and onion and cook, stirring, for 1 minute. Add the beans and 1 teaspoon salt and cook for another 3 minutes. Add the wine, scraping up any browned bits, and let simmer for 30 seconds. Add the stock and simmer for another 10 minutes, stirring occasionally. Transfer the mixture to a blender with the butter and blend on high until smooth.

To make the chimichurri, combine the parsley, basil, shallot, chili, remaining ¾ cup of the olive oil, vinegar, calamansi, and remaining 1 teaspoon salt in a medium bowl. Mix thoroughly.

When ready to serve, rinse the octopus with cold water and thoroughly pat it dry with paper towels. Use a blowtorch or grill to char the octopus.

To serve, spread the bean puree on the serving platter, place the octopus on top and finally dress with the chimichurri.