Preheat a water bath to 170°F (76.67°C)
Cut the "hood" of the octopus off right above the eyes. This can be turned inside out and rinsed, and then cooked along with the tentacles (it's great to chop up in a seafood salad!).
Cut down below the eyes to remove that portion of the octopus and discard.
In the center of the "ring" of tentacles, you'll find an opening (the octopus' mouth). Push through this opening with your finger to ensure the beak - a hard, plastic-like structure - is removed.
You can now separate the tentacles individually or into pairs.
Separate the tentacles into 1 - 2 bags and add the oil.
Seal the bags (or use the water displacement method) then cook for 6 hours.
AT LEAST 2 HOURS BEFORE SERVING
Mix all ingredients together in a bowl or mason jar.
Stir well (or shake the jar) to combine all ingredients.
Ideally, let it sit for at least 2 hours in the fridge, or up to 24 hours before serving.
Preheat your grill to high heat, or set a cast iron pan to heat up on a burner over high heat.
Remove the octopus from the sous vide bag and dry well. Sprinkle with salt.
Once hot, lightly oil the grill or pan and add the octopus.
Sear for 30 - 60 seconds on each side or until charred. You can also use a kitchen torch to help out with this - CLICK HERE for Jason's torch recommendations.
Remove the octopus and serve alongside the chimichurri and your chosen side dishes.