Feel free to mix it up here. Try red snapper or shrimp in place of the striped bass, or swap out the rice for quinoa, farro, or a mix of grains.
Crema: Whisk together sour cream, salt, sugar, lime juice, and 1 teaspoon water.
Bowl: Preheat broiler. In a small bowl, stir together cumin, coriander, chili powder, 1 teaspoon salt, 1/8 teaspoon pepper, and oil. Rub all over both sides of fish. Let marinate in the refrigerator, at least 30 minutes.
Meanwhile, let onion and jalapeno sit in lime juice 10 minutes. Stir in beans, tomatoes, and cilantro. Season with salt and pepper.
Broil fish until browned and cooked through, 3 to 4 minutes. Flake into 4 servings. To serve, place 1/2 cup rice in a bowl. Top with bean mixture, fish, cabbage, avocado, and radishes. Serve with crema on top or alongside.