Wash and dry all produce. Peel and mince or grate ginger. Heat 1 TBSP butter in a small pot over mediumhigh heat. Add half the ginger and cook until softened, 30-60 seconds. Add rice, 3/4 cup water (11/2 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, pat tilapia very dry with paper towels. Cut each fillet into four pieces; season all over with salt and pepper. Set aside. Quarter lime. In a small bowl, combine mayonnaise, sour cream, a squeeze of lime juice, a pinch of salt, and sriracha to taste. Add water 1 tsp water at a time until mixture reaches a drizzling consistency.

In a large bowl, whisk together sesame oil, juice from half the lime, a drizzle of olive oil, 1/2 tsp sugar (1 tsp for 4 servings), and a pinch of salt and pepper. Add mixed greens, carrots, and remaining ginger to bowl with dressing; toss to coat. Season generously with salt and pepper. Taste and add more lime juice if desired.

In a second large bowl, combine tempura mix, 1/3 cup cold water (2/3 cup for 4 servings), and 1/2 tsp salt (1 tsp for 4). Heat a 1/3-inch-layer of oil in a large, heavy-bottomed pan over medium-high heat. Patting dry again first if necessary, stir tilapia into batter until fully coated. Line a plate with paper towels.

Once oil is hot enough that a drop of batter sizzles when added to the pan, working in batches if necessary, add coated tilapia. Cook until golden brown on first side, 2-3 minutes; flip with tongs and cook until golden brown on second side and cooked all the way through, 2-3 minutes more. Transfer to paper-towellined plate. Immediately season with salt and pepper.

Fluff rice with a fork and season with salt and pepper. Divide between plates with tilapia and salad. Drizzle tilapia with sriracha sauce (or serve on the side for dipping).