Wash and pat dry shrimp. Toss in a bowl with soy sauce.
In a shallow bowl, Stir together cornstarch, black pepper and salt. Add shrimp in the bowl and coat each side.
Heat a non-stick heavy pan with 3 tablespoons of oil on medium heat. Fry shrimp on each side until pink and lightly golden brown. It will take about 5-6 minutes. Remove and set on a plate.
Remove the grease from the pan with kitchen paper. Saute onion, garlic and green chili until fragrant. Switch off the heat. Bring back the shrimp in the pan and stir all together.