In a medium sized mixing bowl, combine rice vinegar, water, and slivered red onions to quick pickle. Let sit for an hour or more depending on desired pickling.
In a small sauce pan, whisk together coconut milk and red curry paste, bring to boil. Stir in tofu and allow to simmer for a few minutes. Turn off stove, set pan aside away from heat.
Assemble taco with tofu and red curry. Top with pickled red onion, crispy rice noodles, bean sprouts and sliced pepperoncini.
Garnish with chopped cilantro and lime wedges.