First make the dressing: Whisk the coconut milk to smooth out any lumps. Stir in the lime juice and chopped coriander stalks and set aside.
Toss the prawns with a pinch of salt, chili flakes, and lime zest in a non-metallic bowl. Heat a non-stick frying pan until hot and add the coconut oil. Tip in the prawns and stir-fry for 1-2 minutes, turning occasionally, until opaque and golden. Remove the prawns from the pan using a slotted spoon and set aside.
Wipe the pan clean with a piece of kitchen paper then heat the tortillas in the pan for about 10 seconds to warm through and soften.
Take a tortilla and scatter over a portion of the avocado and spring onion, followed by the prawns. Sprinkle with the coriander leaves, spoon over the dressing and top with a dash of Tabasco if using. Wrap up and serve immediately.