For the teriyaki prawns, heat a frying pan until hot, add the teriyaki sauce and cook until reduced by half then stir in the prawns and continue to cook for 1-2 minutes, or until the prawns are cooked through.
For the prawn dim sum, blend the prawns and pork in a small food processor to a purée.
Transfer the mixture to a bowl, add the remaining ingredients, except the wrappers, and mix until well combined.
To assemble the dim sum, place a small spoonful of prawn mixture into the middle of a gyoza, then fold in half and seal the edges with wet fingers. Crimp to form a wavy edge.
Steam the dim sum for 4-5 minutes, or until cooked through.
For the prawn toasts, heat 2.5cm/1in vegetable oil in a deep, heavy-bottomed saucepan until a small cube of bread sizzles and turns golden when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
Preheat the grill to high.
Toast the slices of bread on one side and set aside.
Blend the prawns and egg white in a food processor to a fine purée.
Spread the mixture over the untoasted side of the bread, then scatter over the sesame seeds and press down lightly.
Place the bread, prawn-side down, into the oil and cook for 1-2 minutes then flip over and cook for a further minute. Remove from the pan and set aside to drain on kitchen paper.
Heat the rice vinegar, sugar, salt and chilli in a saucepan until the sugar dissolves.
Spoon the teriyaki prawns, dim sum and prawn toasts onto separate serving plates and serve the dip alongside.