Make the poke: Trim and cut the tuna into a 1/4-inch dice. Place in a large bowl. Add the scallions, shallot, sesame oil, soy sauce, bean paste, and mirin; stir to combine. Refrigerate while you prepare the rest of the recipe.
Next, make your crunch topping: Place a small skillet over medium heat. Add the nuts, chiles, dried seaweed, sesame seeds, dried shrimp and salt. Toast, shaking the skillet occasionally, until the ingredients start to brown, about 2 minutes. Remove from the heat and let cool slightly in the skillet. Transfer to a mortar and add the sugar. Crush with the pestle until coarse crumbs form.
Next, make the seaweed and edamame salad: Combine the hijiki seaweed, edamame, olive oil and lime juice in a medium bowl; stir together and season with salt.
For serving: Place the cooked rice in individual serving bowls. Top each bowl with the chilled poke, seaweed salad, avocado slices and a tablespoon of crunch topping. Garnish with scallions and a slice of lime.