Rinse the rice under cold water until water runs clear. Drain thoroughly and transfer to a medium saucepan.

Add water and a pinch of salt to the saucepan. Bring to a boil over medium heat, then reduce to low and cover. Simmer for about 20 minutes.

Once cooked, stir in mirin and fluff the rice. Cool to room temperature, preferably in a baking sheet.

Line a loaf pan with plastic wrap and pack the cooled rice down evenly. Chill for at least 1 hour.

Cut the rice into squares after chilling. Heat vegetable oil to 375°F (190°C) and fry rice squares until golden brown, about 3-4 minutes per side.

Sauté the shrimp in a pan over medium heat until they are pink and opaque, about 3-5 minutes. Let cool, then chop.

In a mixing bowl, combine chopped shrimp, green onions, panko breadcrumbs, Kewpie mayonnaise, sriracha, jalapeño, and soy sauce. Mix well.

Top each rice square with shrimp salad, add avocado slicing and jalapeño for freshness, and drizzle with eel sauce if desired. Serve immediately.