01 - Toss cabbage, red onion, cilantro, lime juice, and a pinch of salt in a bowl. Set aside to let flavors meld while preparing other components.
02 - Combine avocado, sour cream, cilantro, lime juice, garlic, salt, and pepper in a blender or food processor. Blend until completely smooth and creamy. Taste and adjust seasoning as needed.
03 - Whisk together flour, cornstarch, baking powder, salt, pepper, and paprika in a mixing bowl. Gradually whisk in the cold sparkling water until you achieve a smooth, lump-free batter.
04 - Pour oil into a deep skillet or pot to reach 2-3 inches depth. Heat over medium-high heat until oil reaches 350°F.
05 - Pat fish strips thoroughly dry with paper towels. Dip each strip into the batter, allowing excess to drip off, then carefully place in hot oil. Fry in batches without overcrowding until golden and crispy, 3-4 minutes per batch. Transfer to paper towels to drain.
06 - Place a portion of fried fish in each warm tortilla. Top generously with slaw and drizzle with avocado crema. Garnish with additional cilantro and serve immediately with lime wedges.