Combine all sauce ingredients except cornstarch and water in a small saucepan. Bring to a simmer. In a small bowl, stir together cornstarch and water. Add to sauce and simmer 2 minutes. Keep warm.
In a medium bowl, whisk together eggs, 2 tablespoons soy sauce, vegetable oil, sesame oil, and 1/3 cup cornstarch. Add cauliflower and toss to coat. Let sit 10 minutes. Sprinkle remaining 1 tablespoon cornstarch on top and mix in.
Heat 1-2 inches of oil to 350 degrees in a Dutch oven or deep pan.
Fry cauliflower in batches until golden brown, being careful not to fry it too long or it will get too soft. Drain on paper towel-lined plates.
Serve cauliflower over rice and drizzle with sauce and sprinkle with green onions.