Mix the lime zest, lime juice and a pinch of salt in a glass or ceramic bowl, stirring well, then add the coconut milk. Add the cubed fish and toss well. Cover and refrigerate for two to three hours, tossing once or twice. Drain off most of the marinade and refresh the fish with a little extra lime juice.
Note: DO NOT use stainless steel, aluminum and plastic bowls; the acidic properties of lime juice can have a chemical reaction and taint the taste of the fish.
Add the chili, tomatoes, avocado, red onion, garlic and cilantro leaves to the fish and gently toss. Arrange on four serving plates, drizzle with olive oil, season with salt and pepper and serve. Enjoy!