In a small bowl, mix together the sesame oil, soy sauce, and ginger. Whisk it with a fork until it's well blended; set aside.
Cook rice as per the packages instructions. (You'll only be using 1 cup of cooked rice, so any extra rice can be stored in the fridge for other purposes, or for another bowl of this good stuff the following day.)
Once the rice is cooked, transfer 1 cup of it to a bowl. Top the rice with chopped cucumbers, avocado, carrots, flaked mackerel, and scallions. Drizzle the sesame ginger dressing over the bowl, and garnish with scallions. Squeeze a bit of Sriracha on there for some heat, and enjoy!