Prepare the slaw by whisking mayonnaise (or yogurt), taco seasoning, and lime juice in a medium bowl. Combine cabbage, carrots, green onions, and cilantro in a large bowl. Drizzle 1/4 cup dressing over and toss well. Set aside remaining dressing.

Pat cod fillets dry and brush with olive oil. Season with salt, pepper, and taco seasoning. Cook in a non-stick skillet over medium-high heat for 4 minutes on one side, flip and cook for another 3-4 minutes until opaque.

In the same skillet, sauté red onion, red bell pepper, and jalapeño over medium heat for 1 minute. Add corn and black beans, cooking for another 1-2 minutes. Stir in lime juice and let meld for 30 seconds.

Assemble bowls by dividing slaw among serving bowls, topping with salsa, cod, avocado, and garnishing with lime wedges and cilantro.