Bring a large pot of water to a boil. Add the shrimp and boil until pink and cooked through, about 3 minutes. Drain, rinse with cool water, and set aside.
In one large bowl, whisk the egg with 1-2 tablespoons water. In a second large bowl, combine the flour, Chinese five spice, salt and pepper. In a third large bowl, whisk together the sweet and sour sauce, chili paste, brown sugar, mirin, and essential oils. Transfer the sauce from the third bowl to an airtight jar and refrigerate until ready to use.
Add the cooled shrimp to the bowl with the egg mixture. Gently stir the shrimp into the egg mixture until each one is fully coated. Using a large slotted spoon, transfer the shrimp - a few at a time - to the bowl with the flour mixture, tapping the spoon on the side of the bowl to shake off any excess egg mixture. Use another spoon to gently toss the shrimp around in the flour to coat them. Repeat this process until all of the shrimp are coated in the flour mixture.
Place the shrimp in a single layer on a large baking sheet. Freeze for a minimum of 2 hours, then transfer the shrimp to a large ziplock bag. Return them to the freezer until ready to use.
To prepare the shrimp, pour enough canola oil into a dutch oven until it is 2 inches deep. Heat the oil until it reaches 325 degrees F. Carefully add the frozen shrimp to the hot oil and fry for 3 minutes, or until golden brown. To be certain that the shrimp are evenly heated through, do not crowd them into the pot. You may have to do this step in batches. Use a slotted spoon to transfer the shrimp from the hot oil to a plate lined with paper towels.
Once all of the shrimp are fried, immediately transfer them to a bowl. Pour the spicy sweet and sour sauce from step 2 over the shrimp and gently toss to coat. Serve over mixed greens and sprinkle with chopped, fresh chives.