Heat the olive oil in a frying pan on medium heat. Chop up the prawns in small bite sized pieces. Add them to the pan and start to saute. Add the minced garlic, lime, salt and pepper. Saute until the prawns turn a bright pink, but don't over cook. Set aside to cool.
Get out a big bowl. Add the chopped onion, tomatoes, red pepper, pineapple, cilantro, lime, and salt.
When the prawns are cooled, add them to the salsa. Mix it all up well. Season with salt and lime to taste.
Make the creamy cashew sauce with sriracha and cilantro according to the directions.
When you are ready to serve the dish, slice the avocados in half and remove the pit. Gently scoop out the flesh with a spoon so that you have a full half an avocado. Cover each avocado in lime juice really well so they don't get brown.
Scoop a couple spoonfuls of the the salsa onto each of the avocado halves. Drizzle cashew cream over top if desired.