Shell and devein the prawns, leaving the tails on, wash and pat dry
Put some olive oil in a large wok (about 1cm, or enough to cover the prawns)
Put the thinly sliced garlic and chillies into the oil and heat it up slowly, trying not to cook the garlic and chillies, but instead trying to infuse their flavour into the oil. If the oil starts to bubble, then turn it down. This should take about 10 minutes
Add the king prawns and cook until coloured (a couple of minutes).