1. Cook rice
In a small saucepan, combine rice, 1¼ cups water, and ½ teaspoon salt; bring to a boil over high heat. Reduce heat to low, cover, and cook until rice is tender and water is absorbed, about 17 minutes. Keep covered until ready to serve.
2. Prep ingredients
Meanwhile, trim scallions, then cut into 1-inch pieces. Halve snow peas crosswise. Finely chop 2 teaspoons each of garlic and peeled ginger. Coarsely chop 1 tablespoon cashews and reserve for step 6; leave remaining cashews whole. Pat chicken dry and season all over with salt and pepper.
3. Stir-fry chicken
Heat 1 tablespoon neutral oil in a medium nonstick skillet over medium-high. Add chicken in a single layer and cook until just browned, about 3 minutes (chicken will not be cooked through).
4. Stir-fry veggies
To skillet with chicken, add snow peas and scallions. Cook, stirring occasionally, until veggies are just tender and blistered, and chicken is cooked through, 2–3 minutes.
5. Finish stir-fry
Reduce skillet heat to medium. Add chopped ginger and garlic and remaining whole cashews; cook, stirring, until fragrant, 1–2 minutes. Stir in Hoisin sauce, sesame oil, ¼ cup water, 1 teaspoon vinegar, and sugar. Bring to a simmer and cook until sauce is thickened and coats chicken and veggies. Season to taste with salt and pepper.
6. Finish & serve
Fluff rice with a fork. Serve rice topped with cashew chicken. Garnish with reserved chopped cashews. Enjoy!