Preheat oven to 425℉. Prepare a baking tray or glass baking dish with parchment paper or aluminum foil. Drizzle or lightly spray with oil.
In a medium bowl, prepare the two flax eggs by whisking together flaxseed and water. Let sit for at least three minutes to thicken.
In another medium bowl, toss together the crushed crackers, garlic powder, onion powder, dried parsley, paprika, and pepper until combined.
Dip one of the fish fillets in the flax mixture, turning to coat both sides. Transfer the fillet to the bowl with the breading and turn to coat. You may need to press the coating on the fish and turn a few times until it's fully breaded.
Transfer the breaded fillet to the prepared baking sheet. Repeat the breading process with the remaining fillets.
Gently drizzle the remaining oil (or lightly spray) over the breaded fish.
Bake at 425℉ for 15-20 minutes, or until the fillets are golden brown and the internal temperature reaches 145℉.
Remove fish from the oven and let cool slightly before assembling your tacos with the remaining ingredients.