Step 1: Prepare the Sushi Rice

1. Rinse the Rice: Rinse the sushi rice under cold water in a fine mesh sieve or bowl until the water runs clear. This removes excess starch and prevents the rice from becoming gummy.
2. Cook the Rice: Combine the rinsed rice and water in a medium saucepan. Bring to a boil, then reduce the heat to low, cover, and simmer for 18-20 minutes, or until the water is absorbed. Remove from heat and let the rice rest, covered, for 10 minutes.
3. Season the Rice: In a small bowl, mix the rice vinegar, sugar, and salt until dissolved. Gently fold the mixture into the cooked rice using a wooden spoon or spatula, being careful not to mash the rice. Let the rice cool slightly to room temperature before assembling the bowls.

Step 2: Make the Spicy Tuna

1. Dice the Tuna: Use a sharp knife to cut the sushi-grade tuna into small cubes. If you prefer a texture similar to a spicy tuna roll, you can finely chop or mash the tuna.
2. Mix the Sauce: In a medium bowl, whisk together the mayonnaise, Sriracha, sesame oil, soy sauce, rice vinegar, and honey or sugar if using. Taste and adjust the spice level by adding more Sriracha if desired.
3. Combine: Add the diced tuna to the bowl with the sauce and mix gently to coat evenly. Sprinkle with sesame seeds and set aside.

Step 3: Prepare the Toppings

1. Slice the avocado, cucumber, and carrot into bite-sized pieces or thin slices.
2. Cook the edamame according to package instructions and let it cool.
3. Cut the nori sheet into thin strips or crumble it into small pieces for garnishing.

Step 4: Assemble the Bowls

1. Base Layer: Divide the sushi rice evenly among four bowls.
2. Add Tuna: Spoon the spicy tuna mixture onto the center of the rice.
3. Arrange Toppings: Arrange the avocado, cucumber, carrot, edamame, and any other toppings of your choice around the tuna.
4. Garnish: Top with nori strips, sesame seeds, green onions, and a drizzle of spicy mayo or wasabi mayo. Serve with pickled ginger and soy sauce or tamari on the side.