All products on this page have been selected by our editorial team, however we may make commission on some products.
Fill a saucepan with 1 litre of water, add a pinch of sea salt and and bring to the boil.
Prepare a bowl of iced water.
Drop the prawns into the boiling water and cook them for about 25 seconds. Quickly transfer them to the iced water to give them a thermal shock. Immediately take them out of the iced water and drain as well as possible. Cut the prawns into cubes that are no larger than 1cm.
Put all of the remaining ingredients for the prawns in a bowl along with the cooked prawns and mix together. Taste and adjust the salt if needed.
Place the tostadas on a serving plate, spoon some of the avocado salsa over each one, then top with the prawn mixture and add more sauce if you wish. Garnish with the chopped coriander leaves and serve with your favourite spicy sauce if preferred.