Spicy Tuna Sushi Stack

Name: Spicy Tuna Sushi Stack
Ingredients: 2 6oz sushi grade tuna steaks (cubed); 1 tbsp low sodium soy sauce; 1 tbsp huy fong chili sauce or 1 tbsp sriracha; 1 tsp sesame oil; 6 scallion stalks (thinly sliced, greens and whites separated); 2 avocados (peeled, seed removed, mashed chunky); 1 english cucumber (diced (1 1/2 cups)); 1 cup sushi rice (prepared to package instruction); 2 tbsp rice vinegar; 2 tsp granulated sugar; 1/2 tsp kosher salt; 2 tbsp Japanese mayo (or regular mayo); 1/2 tbsp sriracha (you can add more if you want it spicier); Sliced nori strips; Sesame seeds