- Make the pickled chiles: Heat the vinegars, sugar, and salt to a rolling boil. Pour over chilies and onions. Allow to sit at room temperature for a few hours or overnight. You will have some chiles left over to use for another purpose.
- Make the pickled pepper mayonnaise: In a small bowl, combine mayonnaise with pickled peppers, garlic, and chile vinegar. Set aside.
- Prepare the cucumbers: In a small bowl, combine cucumbers, onions, mint, lemon juice, salt, and sugar. Set aside at room temperature for about 10 minutes.
- Fry the oysters: Heat a deep fryer or oil in a dutch oven to 350 degrees. In a large bowl, combine cornmeal and flour. Remove oysters from their liquor and toss in flour mixture until completely coated. Fry oysters, in batches if necessary, until they are lightly golden brown and crispy, about 2 to 3 minutes. Remove to a paper towel-lined plate and season with salt and black pepper.
- Assemble: On a large platter, cover the bottom with cucumber mixture, then place fried oysters on top. Drizzle mayonnaise on top and serve.