Whisk together the batter ingredients until smooth, then add the chicken pieces. The batter should be thin and only lightly coat the chicken.
Bring a pot of salted water to a boil and add the carrots and snap peas and cook for just 2 to 3 minutes until they become crisp tender. Drain and set aside.
Meanwhile heat the 2 cups of vegetable oil in a pot or deep fryer to 375 degrees F. Fry the chicken a few pieces at a time, about 3 minutes, until golden brown and cooked through. Drain on a paper towel lined plate. Keep warm.
In a large wok heat the 2 tsp of oil over medium heat and cook the garlic and green onion until fragrant. In a separate bowl whisk together the remaining sauce ingredients, excluding the corn starch and water. Pour into the wok and cook until it lightly bubbles. Mix the corn starch and water together and stir into the sauce mixture. It should thicken up, then add the chicken pieces, snap peas and carrots to the wok and stir gently to combine and heat through.