How to Make It
In a mortar, smash the garlic to a paste with the habanero, cumin seeds and 1/2 teaspoon of salt. In a saucepan, heat the olive oil until shimmering. Add the garlic-chile paste and whisk over moderately high heat for 30 seconds. Let stand off the heat for 10 minutes. Whisk in the citrus juices and let cool, then stir in the cilantro and mint and season with salt and pepper.
In a large bowl, cover the eggplant with water and add a small handful of salt. Let soak for 45 minutes.
Meanwhile, in a small saucepan, bring the citrus juices, ginger, chile, soy sauce and the 2 tablespoons of olive oil to a boil. Simmer over moderate heat, stirring, until reduced to 2/3 cup, 12 minutes. Season the orange glaze with salt and let cool.
In a large saucepan, heat 1 inch of canola oil to 375°. Drain the eggplant and pat dry. In a colander set over a large bowl, toss
the eggplant with the cornstarch, shaking off the excess. Working in 2 batches, fry the eggplant over moderately high heat,
turning, until lightly browned and crisp, 5 minutes per batch. Using a slotted spoon, transfer the eggplant to a paper towel–lined baking sheet to drain.
Light a grill or preheat a grill pan. In a skillet, heat half of the orange glaze. Add the fried eggplant and toss over high heat until hot, 3 minutes. Fold in the cilantro and season with salt; keep warm.
Brush the mackerel with olive oil and season with salt and pepper. Oil the grill grate or grill pan. Grill the fish skin side down until lightly charred on the bottom, 4 minutes. Brush the fish with the remaining orange glaze, flip and grill, brushing with the orange glaze, until just cooked through, about 3 minutes longer. Transfer to a platter and serve right away with the fried eggplant and mojo.