Prawn aguachile with cucumber and pickled onions

Fruit and vegetables

1 avocado, peeled and stone removed, diced

4 red chillies

1 guajillo chilli, toasted

100g/3½oz cucumber, peeled

1 tbsp finely chopped fresh dill

2 tbsp finely chopped fresh coriander

2 garlic cloves

6 limes, juice only

6 limes, juice only

1 red onion, thinly sliced