In a bowl, whisk together the water, 1/3 cup of corn starch, the flour, the sesame seeds, and 1 tablespoon of the oil. Set aside.
In a sauce pan, over medium heat, combine the remaining 2 tablespoons of oil, minced garlic, green onions, orange zest and juice, soy sauce, brown sugar, and vinegar. Bring to a slight boil.
Stir 1 tablespoon of cornstarch into 1 tablespoon of water until dissolved. Whisk into the sauce and reduce heat to a very lower simmer.
Next, heat the vegetable oil in a deep pot to 375 degrees. (You can also use a deep fryer if you have one.)
Coat each cauliflower floret in the flour mixture.
Carefully place each floret into the hot oil. Fry each piece until golden brown - about 3 minutes. Remove from the oil and allow to drain on a paper towel lined baking sheet.
Once all of the pieces are fried, increase the temperature of the oil to 385 degrees and re-fry the nuggets of cauliflower for another 30-60 seconds. This will provide a deeper colour and a better crunch. This step is completely optional!
Lastly, plate the cauliflower and spoon the thick, hot sauce over top. Garnish with some sesame seeds and thinly sliced green onions. Serve immediately.
If serving as a main, this dish will serve 4 people.