Combine soy sauce, orange and lime juices, green and sweet onion, brown sugar, sesame oil and ginger in a large bowl. Add the halibut and gently toss. Cover, refrigerate and marinate for 4 hours, turning occasionally.
Meanwhile, one hour before the halibut poke is done marinating, place the rice in a small pot and cover with cold water. Use your hands and rub the grains together to remove excess starch from the rice. Drain the water from the rice. Add 1 3⁄4 cups (425 mL) of fresh cold water to the pot. Bring the rice to a boil over high heat, and then turn the heat to its lowest setting. Cover and steam the rice until tender, about 15 minutes
While the rice cooks, place vinegar, sugar and salt in a second small pot. Bring to a boil for a few seconds to dissolve the sugar. Remove from the heat. When cooked, spoon and spread the rice into a large, shallow-sided pan. Stir in the vinegar mixture and then cool rice to room temperature.
To serve the poke, add the Fresno (or jalapeño) pepper, nuts, avocado and mint to the marinated fish and gently toss to combine. Divide the rice between 4 bowls. Divide and top with the halibut poke mixture. Garnish each bowl with some pea shoots and serve.
Instead of halibut, try making the poke with another type of boneless fish, such as ahi tuna loin.