1 pound sushi-grade ahi tuna, skinned and cut into 1/2-inch cubes

1/4 cup thinly sliced sweet onion (from 1 medium [8-ounce] onion)

2 tablespoons ogo-nori, rehydrated and squeezed dry

2 teaspoons roasted macadamia nuts, chopped

1 teaspoon minced fresh ginger (from 1 [1-inch] piece)

1/4 teaspoon crushed red pepper

Pinch of Alaea salt, fleur de sel, or smoked sea salt

3 tablespoons sliced scallion (from 1 scallion), divided

2 teaspoons toasted sesame seeds, divided

3 tablespoons toasted sesame oil

3 to 4 tablespoons shoyu, to taste 

Steamed white rice

1 teaspoon chili pepper water (such as Mitch’s Wai Ehu)