Whisk together ingredients for sauce into a bowl and set aside.
In wok, add oil and lightly fry cubed tofu for about 3 minutes, continually tossing. Set aside.
Add carrots to wok and cook on med. high heat for 3 minutes. Add onion, scallions, garlic and ginger. Cook for about 2 minutes and then add remaining vegetables, water chestnuts, chilis. Continue cooking for additional 2 minutes until vegetables are soft.
Add tofu back into stir fry.
Pour sauce over to coat stir fry, may not need all sauce.
Cook until sauce is reduced to desired consistency.
Spoon stir fry over 1 cup of steamed rice and garnish with chopped cashews.