Rinse the rice really well until the water runs clear. Put it in a pot with water and let it soak for thirty minutes. Bring water to a boil and let boil until almost all the water has evaporated.
Cover and let sit until fully cooked. Fluff with a fork when ready to use.
Break up pieces of jackfruit and take any hard bits and seeds. You want the Jackfruit to be stringy, like pulled pork.
In a pan, put jackfruit in and cover with water. Add the soy sauce and salt. Bring to a boil and let cook until softened. The color will darken, as well. Add more water if needed. At the end, add the nori and turn the heat off.
Drain the water out and remove the nori sheets. Add back to the pan on low heat to dry out. Add the sesame oil, beet powder, dulse flakes, and more salt if needed. Stir to combine.
Once it's ready, let cool and then add the siracha and mayo.
All that is left is to assemble. Dip your hands in some water, then in some salt. Scoop a handful of rice and lay it flat on your palm. Spoon in a portion of filling and put some more rice on top. Carefully shape the rice into your desired shape.
Add your nori and sesame seeds (if using) or any other dressings or flavors you want to add.
These are best served when the rice is warm and tend to fall apart once they get cold. But you can always store leftovers in the fridge and heat it in the microwave or in a pan. You probably won't be able to shape it, but you can make an onigiri bowl.