Toast the tortillas in a dry skillet over medium heat until browned on each side. Stack the tortillas and cover with foil to keep warm.
Make the cumin lime coleslaw next. For the dressing, stir together the mayonnaise, 1 Tbsp lime juice, cumin, cayenne, salt, and sugar.
Place the coleslaw mix and sliced green onions in a bowl, pour the coleslaw dressing over top and stir to combine. Refrigerate until you're ready to build your tacos.
Next, season the fish fillets. Combine the chili powder, cumin, garlic powder, and salt. Cut each fish fillet into smaller taco-sized pieces. Season both sides of the fish with the spice mix.
Add half of the cooking oil to a large skillet and heat over medium. Once hot, add half of the fish and cook for a few minutes on each side or until the fish is cooked through (it will feel firm, look opaque, and be easily flaked). Repeat with more oil and the second batch of fish.
Top each toasted tortilla with a piece of fish, a slice of avocado, a small scoop of the cumin lime slaw, and a couple slices of jalapeño. Enjoy warm.
*Corn tortillas are the traditional option for tacos, but go ahead and use whatever you like best. So if you like flour tortillas or crunchy taco shells better or happen to have those on hand, use them! Keep in mind that if you use larger tortillas you'll get fewer tacos out of the ingredients listed above.*You can use just about any type of white fish for this, like tilapia, mahi mahi, or halibut. Try to use fillets that are similar in thickness so the pieces finish cooking at the same time.