Pickled Radishes

1 lb radishes sliced thin
1/4 C cilantro chopped
1 ea. jalapeno stem removed, finely diced
1 C distilled white vinegar or more as needed
2 T sugar
2 T kosher salt
1 tsp red pepper flakes optional
1 T mustard seed

Wash and dry the radishes.  Slice thin and add to a large bowl along with the chopped cilantro and jalapeño and set aside.  In a small saucepan, combine the vinegar with the sugar and salt and stir until dissolved. Bring to a low boil on the stove, then turn off and allow to cool completely (you can also toss in the fridge if you are in a hurry).  Grab a wide-mouth quart canning jar and pack it to the top with the radish/cilantro/jalapeño mixture. Pack tightly. Sprinkle the red pepper flakes and ground mustard on the top of the packed radishes.  Pour the cooled vinegar mixture over the top of the mixture in the jar, if needed, top off with additional vinegar and a pinch of salt.  Place the lid and ring tightly on the jar and allow to sit at room temperature for 24 hours before placing in the refrigerator.  Consume within 7-10 days.