Slice 2 hothouse cucumbers into very thin circles – a mandoline makes quick work of this! I try to get them as thin as possible while maintaining an intact circle.
Toss the cucumbers with 1 teaspoon kosher salt and mix well. Place cucumbers into a sieve resting over a large bowl. Let sit for at least one hour to allow liquid to drain.
Meanwhile, place 1 medium red onion, thinly sliced in a jar with a lid (I use a mason jar). In a small saucepan, combine 1 cup rice wine vinegar, ⅓ cup water, 1 teaspoon kosher salt, 2 teaspoons granulated sugar, and ½ teaspoon red pepper flakes.
Bring to a simmer over medium heat then carefully pour the hot liquid into the jar of onions. Place lid on, briefly shake, remove lid. If needed, press the onions down so they are fully submerged in the vinegar mixture. Allow to cool for 10 minutes before placing in the fridge for at least 30 minutes.
After cucumbers have drained for an hour, squeeze out the excess moisture using a clean towel or your hands (Ina always says clean hands are a cook’s best friend). Discard cucumber juice and transfer cucumber slices to the bowl. Add pickled onions, ½ cup sour cream, 2 tablespoons vinegar from the pickled onions jar, ¾ teaspoon kosher salt, ¼ teaspoon fresh cracked pepper and ¼ teaspoon Cayenne, mix thoroughly. Taste and add additional salt, pepper, and cayenne if needed
I recommend letting it chill in the refrigerator for an hour to allow the flavors to meld.
