Place onion in small bowl, cover with cold water. Let sit five minutes drain, rinse and dry.
Combine onion, chile, salt, pepper and two tablespoons of lime juice. Add fish to the bowl and toss to combine.
Stir lime juice and olive oil. Pour over fish and toss mixture together. Season to taste with salt and pepper. Cover and refrigerate for 15 minutes.
While the fish is marinating, heat up the canola oil in a frying pan on medium high heat. When the temperature registers 375F(190C) drop in the prawn chips, two at a time. Fry for 20 seconds on each side and drain on paper towels.
Slice the avocado in half, remove the pit and scoop out the flesh of the avocado. Place in a blender.
Begin to mix the avocado on low speed until a vortex forms. Add lime juice, olive and salt pepper and continue to blend until well incorporated. Taste and adjust seasoning to your liking.