Wash and dry all produce. Peel and mince or grate ginger. Halve, peel, and thinly slice onion. Halve, deseed, and thinly slice bell pepper. Trim scallions, then cut into 11/2-inch pieces. Pat chicken dry with paper towels.

Melt 1 TBSP butter in a small, lidded pot over medium-high heat. Add half the ginger. Cook until fragrant, about 1 minute. Add 3/4 cup water and a pinch of salt; bring to a boil. Once boiling, stir in rice. Reduce heat to a simmer, cover, and cook until tender, about 15 minutes. Turn off heat; keep covered until ready to serve.

Meanwhile, add peanuts to a large, dry pan over medium-high heat. Cook, stirring often, until toasted, 2-4 minutes. Season with salt, pepper, and 1/2 tsp sugar. Cook, stirring, 1 minute more. Transfer to a small bowl. Wipe out pan.

Heat a large drizzle of oil in same pan over medium-high heat. Add onion and cook, stirring, until slightly softened, 2-3 minutes. Add bell pepper and cook, stirring, until softened, 2-3 minutes more. Season with salt and pepper. Transfer to a medium bowl.

Heat a drizzle of oil in same pan over medium-high heat. Add chicken; season with salt and pepper. Cook, stirring occasionally, until browned and cooked through, 5-7 minutes. Return veggies to pan, stirring to combine. Add scallions and remaining ginger; cook 1 minute. Reduce heat to medium-low. Stir in teriyaki sauce. Cook until thickened, 2-3 minutes.

Fluff rice with a fork. Season with salt and pepper and divide between plates. Top with stir-fry. Sprinkle with peanuts. Drizzle with sriracha (to taste).