Pat the 8 oz (230 g) raw shrimp dry with paper towels. Cut about two-thirds of the shrimp into small pieces and finely mince the remaining one-third until almost paste-like.

Put all the chopped and minced shrimp into a bowl. Add 1/4 teaspoon salt, 1/2 teaspoon fish sauce, 1 teaspoon sesame oil, and 3 dashes ground black pepper. Stir until the mixture is evenly combined.

Lay one wonton wrapper flat on a clean, dry surface. Place about 1 tablespoon of the shrimp filling in the center of the wrapper.

Fold the wrapper in half to form a triangle, pressing the edges together to remove any air and to seal. Using your thumbs and index fingers, press and squeeze both sides toward the center to create small folds/pleats and ensure a tight seal. Repeat with remaining wrappers and filling. Place finished wontons on a clean baking sheet or plate.

Pour oil for deep-frying into a wok or small stockpot to a depth of 2 to 3 inches (5–7 cm). Heat the oil to 350°F (176°C) using a thermometer.

Working in batches to avoid overcrowding, gently lower several wontons into the hot oil. Fry, turning as needed, until they are golden brown and the filling is cooked through, about 2–4 minutes per batch depending on size.

Remove fried wontons with a slotted spoon or strainer and drain on paper towels. Repeat frying remaining wontons, keeping cooked ones warm if desired.

Serve the fried shrimp wontons warm with the 4 tablespoons mayonnaise for dipping.