Start by cleaning and deveining your prawns thoroughly, ensuring any shell remnants are removed. Pat them dry with paper towels.

In a mixing bowl, combine cornstarch, salt, black pepper, and chili pepper until well blended. Toss the cleaned prawns in this mixture, ensuring they are evenly coated.

Pour enough oil into a wok or deep skillet for frying (around 2-3 inches deep) and heat over medium-high heat until it reaches 350°F (175°C).

Carefully add the coated prawns to the hot oil in batches, frying each batch for about 2-3 minutes on each side until golden brown.

Allow the fried prawns to rest on paper towels for a minute to retain their crunchiness.

In the remaining hot oil, sauté minced garlic and ginger for about 30 seconds until fragrant, ensuring they do not burn.

Return the fried prawns back into the wok and toss them with the garlic and ginger to combine flavors before garnishing with sliced green onions.