Heat the oil in a wok over medium-high heat to 350°F (180°C). Fry the shrimp in 2 batches, making sure each batch is fully submerged in the oil. Cook each batch for 2 to 3 minutes, stirring gently to keep the shrimp from sticking together; when they’re done they’ll be pink and lightly golden. Transfer the fried shrimp to a paper towel-lined plate.
When both batches are done, pour off the oil and strain it for another use, reserving about 1 tablespoon. Wipe the wok clean.
Return the wok to medium heat with the reserved tablespoon of oil. Add the garlic and stir-fry for about 10 seconds, until fragrant. Add the red and green peppers and stir-fry for about 1 minute. Return the shrimp to the wok and sprinkle them evenly with ½ teaspoon of the jiaoyan seasoning, toss well, then add another ½ teaspoon of the jiaoyan and toss again. Taste and add more seasoning as needed. Garnish the shrimp with the sliced scallion greens and some sesame seeds before serving.