Preheat oven to 425°F. Invert muffin tray onto baking sheet; grease with nonstick cooking spray. Drape each tortilla over muffin cup and shape around cup to form a bowl. Bake for 10 to 12 minutes or until crisp. Let cool for 2 minutes; remove carefully from muffin cups. Let cool for 5 minutes.
Meanwhile, prepare cod according to package directions. Let cool slightly. Flake into chunks.
Place each tortilla bowl on plate. Divide coleslaw among bowls. Top with cod and spoon sauce over top. Top with avocado, tomato, feta and green onions.
Customize toppings as desired – try corn, black beans, pickled jalapeño peppers, cilantro, shaved radish, red onion or rice.