2 bulbs fennel, stalks and fronds removed
1 large shallot, shaved on a mandoline or sliced thinly as possible
1 ½ cups hot water
½ cup rice vinegar
1 tablespoon white wine vinegar
1 ½ tablespoons salt
1/3 cup sugar
3 cloves garlic, smashed
1 tablespoon peppercorns
1 tablespoon orange zest
1 teaspoon red pepper flakes