For the sushi rice:

1. Place rice and 2 cups water into a medium saucepan over high heat and bring to boil. Reduce heat, cover and let simmer for 15 minutes. Remove from heat and let stand, covered, for about 10 minutes.
2. Meanwhile, in a small bowl, combine rice vinegar, sugar and salt. Heat in small saucepan over low heat or in microwave for 30-60 seconds, or until sugar and salt have dissolved.
3. Transfer cooked rice into a large glass or wooden bowl and add vinegar mixture. Fold thoroughly to evenly coat rice and help it dry.

For the spicy mayo:

1. In a small bowl, whisk together Greek yogurt, mayonnaise and Sriracha until combined. Set aside.
2. For the guacamole:
3. In a small bowl, mash avocado with a fork until creamy. Add lime juice, cilantro and salt until combined. Set aside.

For the burrito:

1. In a medium bowl, whisk together ginger, garlic, sesame oil, soy sauce and green onion until combined. Add tuna and let marinade in refrigerator for 20-30 minutes.
2. To assemble burritos, lay a sushi mat on your surface. Lay a sheet of nori shiny-side down and spread about 1 cup rice down in an even layer, leaving 2-inch border on all edges (keep a small bowl of water beside you to wet your fingers while gently spreading the rice over the nori). Spread 2 tablespoons guacamole across half of rice. Spread 1 tablespoon spicy mayo across other half. Lay down a row of tuna and a row of vegetables. Roll sushi burrito up from the bottom, using your fingers to keep fillings in place. Watch video above for rolling technique.
3. Wrap burrito in foil and cut into four sections. Repeat with remaining ingredients. Serve immediately or store in refrigerator until ready to serve.