In a small bowl, combine oil, soy sauce, brown sugar, lemon juice, and wasabi powder.

Place salmon in a baking dish and pour half of the marinade over the top. Cover and marinate for one hour in the refrigerator. Reserve remaining marinade to use as salad dressing.

Preheat oven to 400 degrees Fahrenheit. Remove salmon from refrigerator. Uncover and bake for 15 minutes, until salmon flakes easily with a fork.

Rinse rice until water runs clear. Add to a medium saucepan. Add water and bring to a boil. Cover, lower heat, and let simmer until water is absorbed, about 20 minutes.

Let cool and stir in rice vinegar, sugar, and salt.

Arrange rice in each dish. Top with salmon, cucumbers, carrots, and avocado.

Sprinkle with sesame seeds and chopped nori.

Pour reserved dressing over the top.