1. Stir all marinade ingredients together and reserve on side, reserving 2 Tbsp separately for garnish.
2. Add fish to remaining marinade and let sit in fridge.
3. Cut leeks into long, super thin strips. Heat 2 cm of oil in pan over medium high heat. Fry leeks for 1 minute, until crispy and beginning to brown. Remove from oil to paper towel to drain and reserve on side.
4. To fish mixture, add in half the chilies and herbs (reserve rest for garnish)
5. Mix avocado GENTLY into fish mixture.
6. Season to taste with salt.
7. Garnish with some of the reserved marinade, fresh herbs and fried leeks.