Step 1

Whisk scallion greens, tamari, mirin, oil, white sesame seeds, ginger and crushed red pepper, if using, in a medium bowl. Set aside 2 tablespoons of the sauce in a small bowl. Add shrimp to the sauce in the medium bowl and gently toss to coat.

Step 2

Combine rice and vinegar in a large bowl. Divide among 4 bowls and top each with 3/4 cup shrimp, 1/2 cup each tomatoes and avocado, and 1 tablespoon each cilantro and black sesame seeds. Drizzle with the reserved sauce and serve.