Preheat the oven to 400°F. Line a baking sheet with foil and grease well with cooking spray, butter, or olive oil.
Combine the corn flour and dry spices for the cod in a small bowl. Stir to evenly distribute the seasonings.
Working on a large plate or rimmed sheet pan, coat the pieces of fish on all sides with mayonnaise. A pastry brush or clean hands will work well. Sprinkle the seasoning mixture on top of the mayo-coated fish, turning each piece to coat at least the top and bottom.
Transfer the seasoned fish onto the prepared baking sheet. Bake for approximately 8 minutes until the fish is opaque and flakes easily with a fork. Total time will depend on the thickness of the fish. Remove and serve right away.
Make the peach salsa:
Combine all ingredients in a small bowl and stir gently to combine well. Serve right away or store covered in the fridge for 2-3 hours.
To serve:
Wrap the stack of corn tortillas in a damp paper towel. Microwave until warmed through, about 30-60 seconds, depending on the microwave. Keep them wrapped in the damp paper towel until ready to assemble the tacos. This will make the tortillas pliable and keep them from breaking.
Assemble the tacos by layering the warm tortillas with the Cajun cod and peach salsa. Add a slice of avocado (highly recommended) and squeeze of lime if you’d like. Serve with a side of rice.