For the guacamole: In a food processor, mix together the avocados, lime zest and juice, jalapeno pepper and hot sauce. Season with salt and pepper. Keep in the refrigerator.
For the salsa verde: Remove the papery husks from the tomatillos and rinse well. Cut in half and place cut-side down on a baking sheet lined with parchment paper. Place under a broiler for about 5 minutes to lightly blacken the skin. Place the tomatillos, cilantro, lime zest and juice, garlic, onions and jalapeno pepper in a food processor (or blender) and pulse until all the ingredients are finely chopped and mixed. Season with salt. Cool in the refrigerator.
For the Salsa Roja: Preheat the oven to 400 degrees F (200 degrees C). Lay the tomatoes, garlic, serrano pepper and onions on a baking tray lined with parchment paper. Drizzle with the olive oil and season with salt and pepper. Bake in the oven until the tomatoes look soft and the onions and peppers have a nice char, about 30 minutes. Transfer into the recipient of the food processor and reduce into a coarse puree with the cilantro and lime zest and juice. Adjust seasoning. Add a little water if too thick. Keep in the refrigerator.
For the Salsa Mexicana: Mix together the tomatoes, cilantro, garlic, lime zest and juice, onions, jalapeno pepper, red bell pepper and olive oil. Season with salt and pepper. Keep in the refrigerator. For the fish: To make the beer batter, in a large bowl, combine the flour, cornstarch, baking powder and some salt. Blend the beer and eggs, and then quickly stir into the flour mixture (don't worry about a few lumps). Heat the oil in a deep-fryer to 375 degrees F (190 degrees C). Dust the fish pieces lightly with flour. Dip into the beer batter and fry until crisp and golden brown. Drain on paper towels.
To serve: Place the fried fish in a tortilla, add a dollop of mayonnaise, and top with shredded cabbage, onions and cilantro. Top with guacamole, salsa verde, salsa rosa and salsa Mexicana.