Heat water in a small pot over medium heat and bring temperature to 64F.
Season tuna with salt and place in a sealable plastic bag.
Add remaining ingredients, seal and place in simmering water.
Cook for approximately 1 hour, until tuna is cooked.
Remove tuna from oil, flake into a bowl, place in fridge to cool until assembly.
Place potatoes in a pot, cover with cold seasoned water and bring to a boil. Reduce heat to a simmer and cook until fork tender, approximately 20 minutes.
Strain and quarter potatoes. Place in a bowl and set aside.
Place remaining ingredients in a separate pot. Bring to a boil, reserve 1½ tablespoons of pickling liquid for Celery Salad Dressing.
Pour remainder over potatoes and set aside to cool.
Preheat oven to 400F. Line a baking tray with parchment paper and dust with pastry flour.
Place flours, fennel seeds and salt in a stand mixer with dough hook attachment.
Mix on low speed, add olive oil and warm water.
Mix until dough is formed. If dough feels too wet, add more warm water, 1 tablespoon at a time. Or, if dough feels too dry, add more pastry flour, 1 tablespoon at a time.
Remove dough from stand mixer, divide into 4 equal pieces and dust with flour.
Using a pasta machine at the widest setting, flour 1 piece of dough and begin to roll.
Continue to dust and roll out dough as thin as possible without tearing, moving the settings down each time.
Place rolled sheets of dough on a flour dusted baking tray. Repeat rolling process with remaining dough. Brush off excess flour.
Brush sheets of dough with egg white and sprinkle with Maldon salt. Bake until edges are golden and crackers are crisp, approximately 15-20 minutes, rotating tray 1/2 way through baking.
Break into bite size pieces, set aside for assembly.
In a bowl, mix ingredients together and set aside for assembly.
Place celery hearts and frisee in a bowl.
Before serving, spoon desired amount of Celery Salad Dressing in bowl, season with salt and toss.
Place 4 pieces of Pickled Potatoes in the centre of each plate.
Place equal amounts of Tuna Conserva on Pickled Potatoes. Top with Celery Salad.
Place pieces of Fennel and Lemon Crackers beside Tuna Conserva.
Drizzle 1 teaspoon of Celery Salad Dressing around the plate and serve.
