Heat the dashi with the salt in a small saucepan over low heat to dissolve. Keep warm.
Scoop the hot rice into four small bowls with a rice paddle. Lay 4 slightly overlapping sashimi slices over the rice in each bowl.
Sprinkle with chives and cover with enough salted dashi to almost reach the top of the rice (about 1/3 cup).
Sprinkle with nori threads and serve immediately.
1 1/2 cups dashi (see directions for recipe)
1/2 teaspoon fine sea salt
2 cups short-grain rice, cooked
16 slices yellowtail sashimi
4 teaspoons chives or thin scallion tops, chopped into fine rounds
1/4 sheet or 2 teaspoons of nori, snipped into fine threads