Preheat your grill or stovetop pan over medium-high heat.
In a small bowl, combine the cumin, paprika, olive oil, salt, and black pepper. Rub this mixture evenly over both sides of the fish fillets.
Place the seasoned fish on the grill or pan, cooking for about 4-5 minutes per side, or until the fish easily flakes with a fork. Remove from heat and let it rest for a couple of minutes.
Meanwhile, in a medium bowl, mix together the diced mango, red onion, bell pepper, jalapeño, lime juice, and chopped cilantro to create the mango salsa. Season with a pinch of salt to taste.
Warm the corn tortillas either on the grill for about 30 seconds per side or in a skillet over medium heat for a few moments.
To assemble the tacos, break the cooked fish into large pieces and place them in the center of each tortilla. Top with a generous spoonful of mango salsa and a few slices of avocado.
Serve the tacos immediately with lime wedges on the side for squeezing over the top.