First, make four cups of rice in your rice cooker. The ratio is 1:1, so if you measure out four cups of rice into your rice cooker, fill the pot until the water reaches the line marked with a 4. The rice usually takes 15-20 minutes to cook depending on your rice cooker.
In the mean time wash and slice your tuna steak into 1/2 inch cubes and set aside in a bowl.
Next finely chop the red onions, adding to the tuna for poké preparation.
Next add the minced ginger, soy sauce, sesame oil, siracha, lime juice, sea salt, and mirin and mix well until tuna is fully coated.
Prepare your poké bowl by first adding a cup of the cooked rice. Next add about 10 cucumber slices on one side of the bowl and half an avocado's worth of slices on the other, leaving room in the middle to place 3-4 scoops of the tuna mixture (use picture for reference).
Finally top with kewpie mayo and siracha to taste. Sprinkle the sesame seeds, green onions, and shredded dried seaweed to garnish. Eat up!