Add the TVP slices to a deep plate or bowl. Pour in boiling water to cover and let it set for about 1 hour, or until the TVP is rehydrated and tender (soaking time depends on the brand and size of your TVP).
Drain and rinse the slices a couple of times. Squeeze the slices between your hands to remove as much water as possible. Transfer to a food processor.
Add the vegan nước mắm, sugar, onion powder, dried dill, garlic, cornstarch, and dulse if using. Process for 15-30 seconds, or until it forms a flaky paste (a bit like flaked tuna). You want the mixture to hold together when you squeeze it between your hands, but it should still be slightly crumbly.
Cut 14 rectangles of about 2x3-inch in the nori sheets. Dilute one teaspoon of cornstarch in 2 teaspoon of water and set aside.
Place about 1.5 tablespoons of the fish mixture on the bottom of a nori sheet. Dip your finger into the cornstarch water and slightly wet the top side of the nori sheet. Roll it up tightly into a roll. The cornstarch will allow the nori to stick, preventing the roll from unrolling. Repeat with the remaining nori sheets and fish mixture.
Heat a tablespoon of oil in a large non-stick skillet. Once hot, add the fish rolls and sauté for 3-5 minutes, stirring regularly, until the nori is crispy. Remove from heat and set aside.