Heat wok over high heat until almost smoking.
Reduce heat to low and add half the oil.
Increase heat to medium and add raw cashew nuts.
Cook cashew nuts until lightly browned, 2 – 3 minutes; remove from heat.
Add remaining peanut oil and chicken, ginger and garlic.
Sprinkle black pepper; return to heat and cook until chicken turns white.
Add soy sauce and mix.
Add celery, carrot and salt; cook for 1 – 2 minutes.
Add water and oyster sauce; wait for water to bubble and then stir.
Cook until water evaporates.
Sprinkle with scallions and cashew nuts and mix.
Serve over rice.
