Brush some vegetable oil on grill grates or a grill pan and heat the grill over medium-high heat.

Brush the tilapia with the olive oil and sprinkle with the seafood seasoning, cumin and oregano. Grill the tilapia for a few minutes on each side until cooked through.

Fill a deep, heavy fry pan or cast-iron skillet halfway with vegetable oil. Place over medium-high heat and bring the oil to 350 degrees F. Cut 8 rounds out of the corn tortillas. Fry the tortilla rounds in batches until crisp, and then drain on paper towels.

In a food processor, combine the avocado, sour cream and heavy cream. Puree until smooth. Add more heavy cream if needed to make a creamy but not too thin sauce.

Transfer the avocado to a bowl and stir in the cilantro and onions. Season with salt.

In a bowl, toss the mango with the sugar and a pinch of salt.

To serve, top each tortilla with some tilapia, top with avocado sauce and then mango. Garnish with chopped cilantro.