In a large mixing bowl, whisk together mayonnaise or plain yogurt, taco seasoning, and fresh lime juice until smooth. Add the shredded green and red cabbage, pre-shredded carrots, chopped green onions, and fresh cilantro to the bowl. Toss everything together until the vegetables are well coated in the dressing, then set aside to allow flavors to meld.

Pat the cod fillets dry, drizzle with olive oil, and sprinkle taco seasoning on both sides. Heat a non-stick skillet over medium-high heat with a little olive oil. Once hot, place the seasoned side of the cod down in the skillet and cook for about 4 minutes. Flip and cook for an additional 3-4 minutes until fully cooked and flaky.

In the same skillet after removing the fish, sauté diced red onion, red bell pepper, and jalapeño over medium heat for about 1 minute. Add frozen corn kernels and canned black beans, cooking for an additional 1-2 minutes until heated through. Squeeze fresh lime juice over the salsa and stir.

In each serving bowl, spoon generous portions of the colorful slaw, then add smoky black bean-corn salsa on top. Place a cooked cod fillet over the salsa, followed by slices of fresh avocado. Garnish with extra lime wedges and fresh cilantro leaves.