Grilled Tuna Tostadas with Black Bean-Mango Salsa

In a small bowl, whisk the lime zest and juice, cumin, chili powder, garlic, and 1 tablespoon extra virgin olive oil until well combined. Place the tuna fillets in a large Ziploc bag and pour in the marinade. Seal the bag, removing as much air as possible, and gently squish the fillets around to make sure they’re well coated. Marinate at room temperature for 20 minutes, turning the fillets over once halfway through.

Meanwhile, lightly brush the tortillas on both sides with extra virgin olive oil and place them on a large baking sheet. Sprinkle with kosher salt. (I like to add a sprinkling of chili powder too, but that’s optional.) Bake for 6 minutes, then turn the tortillas over. Bake for another 5-8 minutes until lightly browned and crisp. Briefly set aside.

Moving on to the avocado mash. Slice the avocados in half, remove the pits, and scoop the flesh into a bowl. Add the lime juice and a generous pinch of salt and mash until relatively smooth. Season with freshly ground black pepper to taste. Set aside while you cook the fish.

Pre-heat a lightly oiled grill or grill pan over medium heat. (You can also use a nonstick skillet if you prefer.) Remove the fish from the marinade and pat it dry. Season the fillets on both sides with kosher salt and freshly ground black pepper. Place the fish in the hot pan and cook for 2½ minutes per side for medium-rare. (Feel free to cook it slightly longer if you prefer your tuna medium or medium-well.) Transfer to a cutting board and flake into small pieces with a fork.

Time to assemble the tostadas! Spread each tortilla with a generous amount of avocado mash. Top with flaked tuna and mango-black bean salsa. Garnish with extra cilantro and sliced radishes (if using). Serve with lime wedges.