Rinse the sushi rice under cold water until the water runs clear.
Combine the rinsed rice and 1 1/4 cups water in a medium saucepan and bring to a boil over medium-high heat.
Reduce heat to low, cover, and simmer for 18 minutes or until the water is absorbed and rice is tender.
Remove from heat and let rice sit, covered, for 10 minutes.
In a small bowl, mix rice vinegar, granulated sugar, and salt until dissolved.
Transfer cooked rice to a large bowl and gently fold in the vinegar mixture. Allow to cool to room temperature.
In a medium bowl, combine soy sauce, toasted sesame oil, honey, and grated fresh ginger.
Add the cubed tuna to the marinade and toss gently to coat. Let marinate for 10 minutes in the refrigerator.
Divide the sushi rice evenly between two bowls.
Top each bowl with marinated tuna, cucumber slices, shredded carrots, diced avocado, and sliced green onions.
Sprinkle toasted sesame seeds and nori strips over the bowls.
Serve immediately.