1. Place the sushi rice in a fine-mesh strainer and rinse well with cold water until the water runs mostly clear. Drain. Transfer the rice to a small saucepan and add water. Bring to a gentle simmer, cover and reduce the heat to low. Cook for about 12-15 minutes, until the water is absorbed. Turn off the heat and let the rice stand, covered, for 10 minutes. In a small bowl, combine rice vinegar, sugar and a pinch of salt. Add to the warm rice and gently mix. Let the rice cool.
2. Prepare an 8.5 × 6.5 inch (22 × 16.5 cm) Pyrex glass dish and line it with plastic wrap, leaving some overhang around the edges.
3. Arrange the smoked salmon over the bottom of the dish in an even layer, covering as much of the bottom as possible. Arrange the avocado slices over the smoked salmon.

4. Add the cooled sushi rice and spread it evenly over the avocado. Gently press the rice down with the back of a spoon or damp fingers so the layers hold together, but don't pack it too tightly.

5. Cut one nori sheet to fit the dish and place it over the rice. Spread the cream cheese evenly over the nori sheet.

6. Arrange thin cucumber slices over the cream cheese. Cut the second nori sheet to fit and place it over the cucumber.

7. Place a serving board or plate over the baking dish. Hold them together firmly and carefully turn everything upside down. Lift off the glass dish and remove the plastic wrap.

8. Add mayonnaise to a small Ziploc bag and snip off a tiny corner. Drizzle the mayonnaise over the smoked salmon, then drizzle with sriracha and sprinkle with black sesame seeds.

9. Refrigerate for about 20-30 minutes to help the layers set. Use a sharp knife to cut the lazy sushi into squares. Lightly wet the knife between cuts for cleaner pieces. Serve with soy sauce on the side.