First prep your pickled onions. Bring a pot of water to a boil and submerge the sliced onions for a minute. Remove with a strainer and place the onions in a deep bowl or jar. Add the water, vinegar, salt and sugar. Stir well, cover bowl and place in the fridge for at least a half hour to allow them to chill, overnight is even better.
Prepare your tofu stations by placing the flour, corn meal and Old Bay seasoning in one bowl - stirring well to combine. And the beer in another bowl. Place some parchment paper on a large baking sheet - this will be where your tofu can cool.
Add your vegetable oil to a medium soup pot. Turn stove heat to medium-high. When the oil is hot, you can start coating your tofu and placing it in the pot.
Soak your tofu in the beer for a few seconds, then dredge in the flour mixture, then back in the beer for a second, then back in the flour, coating all sides. Then carefully place the coated tofu in the oil pot. Repeat with all the tofu until the pan is filled. Fry for 1-2 minutes on the first side, then flip using a slotted spatula, and repeat. When tofu is golden in color and crispy, remove from the pan and place tofu on the parchment paper to cool. Repeat until all the tofu is done. Sprinkle some sea salt over top the battered tofu if desired.
Start assembling your tacos! Use two layered tortillas per taco. Warm tortillas in oven, microwave or stove stop. Add a slathering of the vegan mayo, then add the cabbage, tofu, avocado, pickled onions and optional hot sauce. Serve warm!