In a bowl, whisk beer, flour and salt, blending well. Rinse fish and pat dry, check for bones by pressing with fingers and pulling out with tweezers. In a deep 5 to 6 quart pan, heat 1 inch salad oil to 360°. Using a fork, coat fish pieces with beer batter and lift out, draining briefly. Slide coated fish into oil, about 5 pieces at a time. Adjust heat to maintain oil temperature. When fritters are golden, in about 2 minutes, lift out with a slotted spoon and drain briefly on paper towels; keep warm. Repeat to fry remaining fish. To assemble each taco, stack 2 tortillas; add a fish fritter, cabbage, mayonnaise, and salsa. Squeeze lime over filling, fold tortillas and eat. Makes 10 servings