Yield: 4 servings.
For the pico de gallo:
4 cups seedless watermelon, diced
1 mango, peeled and diced
1 jalapeño, seeded and diced
½ cup red onion, diced
Juice of 1 lime, plus extra wedges to serve alongside
1 teaspoon cumin
½ cup cilantro, roughly chopped
1 cup romaine lettuce, sliced into ribbons
For the fish tacos:
1½ pounds boneless, skinless, firm white fish
8 (8-inch) corn tortillas
1 cup Cotija cheese, crumbled
Combine watermelon, mango, jalapeño, and onion in bowl. Stir in lime juice and cumin. Set aside.
Preheat an outdoor grill, and lightly oil grill grate. Brush fish with olive oil and season with salt, pepper, and a light dusting of cumin. Lay fillets on grill. Cook about 4 or 5 minutes per side until marked and cooked through. Place the fish into a bowl and break into bite-size pieces.
Fold cilantro and shredded lettuce into the pico de gallo. Warm tortillas on the grill, then fill with fish. Top the tacos with pico, then scatter with crumbled cheese. Serve with lime wedges.