Rinse the octopus under cold water and remove debris. Place in a pot with water, celery, lemon halves, bay leaf, peppercorns, and salt. Bring to a boil and dip the octopus in three times, then cover and simmer for 40-45 minutes until tender.

Once cooked, cool the octopus for 10-15 minutes, then slice into bite-sized pieces.

In another pot, boil water with lemon halves, tangerine halves, bay leaves, and salt. Add the squid and shrimp, poaching for about 2 minutes until shrimp is pink and squid is tender.

Whisk together the dressing ingredients in a bowl: olive oil, tangerine juice, lemon juice, garlic, mustard, salt, and parsley.

In a serving bowl, mix together all seafood and drizzle dressing over. Toss to coat and adjust seasoning as needed.

Allow the salad to rest for 15 minutes at room temperature to meld flavors, or chill in the fridge for up to 12 hours.