Pour off the brine from the can. Place the chunks of jackfruit in a colander or strainer and rinse with water. Thoroughly drain.
Shred the jackfruit with a knife, fork, or your fingers until flaky. Discard any firm seed pods or tough pieces.
Over medium-low heat, sauté the diced onion and garlic in a skillet with olive oil until soft but not browned. Use a spatula to turn the onions and garlic while cooking to prevent them from burning.
Add the shredded jackfruit and tarragon. Combine with the onions and garlic. Cook for 2-3 minutes while continuously moving everything around in the pan. Add more olive oil if needed (just a teaspoon at a time) to prevent the jackfruit from sticking to the pan.
Remove the pan from the heat and set aside.
Place the drained white beans, butter, and salt into a saucepan over med-low heat. Stir while cooking, until the beans are soft.
Remove beans from heat and thoroughly mash with a spoon, fork, or potato masher.
Combine mashed white beans with the jackfruit and let cool for a few minutes.
Stir in the diced celery.
In a small bowl or measuring cup, combine mayo, relish, mustard and lemon.
If desired, add a small amount of nori. Start with just a pinch. Stir and taste. Add more if needed.
Pour the dressing over the jackfruit and beans and mix thoroughly.
Cover and refrigerate the tuna salad at least 1-2 hours until fully chilled. Serve and enjoy!
