Fill a medium bowl with ice and water, then add the shrimp and let soak for 15 minutes. While brining, proceed to make crispy basil.
To make the crispy basil: Wash and pat very dry the basil leaves. The leaves MUST be very dry, or the oil will splatter. Add 4 tablespoons of cooking oil to the wok. When the oil is hot and shimmering (but not smoking quite yet), add a single basil leaf to test. Deep fry the basil leaves in batches and let them cool on a plate with paper towels to absorb the excess oil.
Drain and pat dry the shrimp on paper towels. Empty the bowl, wipe it dry and return the shrimp, the remaining 1/4 teaspoon of salt, sesame oil and cornstarch. Stir to coat the shrimp.
Heat a wok over high heat until a bead of water sizzles and evaporates on contact. Add the cooking oil, swirling to coat the wok. Add the shrimp and immediately give each piece space on the wok, so they aren't touching. Let fry, untouched for 1 minute. Flip and let fry for an additional minute, or until just cooked through. Remove from wok, leaving as much oil in the wok as possible.
There should still be 1 tablespoon of cooking oil in the wok. If not, add more. Return the heat to medium-high and let the oil heat up. Add in the chili pepper and garlic and fry until fragrant, about 15 seconds. Add in the zucchini slices and stir fry for 1-2 minutes, tossing every 15 seconds until the zucchini is just barely soft in the middle but still firm on the edges.
Pour in the soy sauce into the wok. Add back the cooked shrimp. Toss everything to allow the sauce to coat the shrimp and zucchini. Top with crispy basil.
