Adjust rack to top position and preheat oven to 425 degrees.

In a small pot, combine rice, ¾ cups water (1½ cups for 4 servings), and a pinch of salt. Bring to a boil, then cover and reduce to a low simmer. Cook until rice is tender, 15-18 minutes.

Keep covered off heat until ready to serve.

Meanwhile, wash and dry produce.

Trim and quarter cucumbers lengthwise; slice crosswise into ½-inch-thick quarter-moons. Trim and thinly slice scallions, separating whites from greens. 

In a medium bowl, combine cucumbers, scallion whites, carrots, dressing, 1 tsp vinegar, and ¼ tsp sugar (2 tsp vinegar and ½ tsp sugar for 4 servings). (Be sure to measure the vinegar—we sent more.) Season generously with salt and pepper.

In a small bowl, combine hoisin, miso sauce concentrate, and umami ginger sauce; set aside. 

Pat trout* dry with paper towels; season all over with salt and pepper.

Place trout, skin sides down, on a baking sheet. Evenly spread tops of trout with hoisin miso glaze. Roast on top rack until trout is cooked through, 10-12 minutes.

Fluff rice with a fork.

Divide rice, trout, and cucumber carrot salad between plates. Sprinkle everything with scallion greens and serve.