Start by chopping the pineapple into bite-sized pieces. Dice the onion and the cilantro. Mix all of the ingredients. Salt to taste. Then let it chill for 15 to 20 minutes to blend.
Liberally season both sides of the mahi-mahi with salt, pepper, granulated garlic and Cajun seasoning.
Use a cast iron skillet to fry the mahi-mahi at medium-to-high heat (this will make it a nice crispy crust with a flaky inner shell). Cover with a lid to let steam for a couple of minutes.
Remove from the heat and place the mahi-mahi on top of the pineapple mixture.
Serving Suggestions: Serve with lime slices garnished with parsley. This goes well with rice of your choosing and a side salad of your choosing.