In a medium size serving bowl, combine the buttermilk, lime juice,
cilantro, onion, garlic, salt and pepper. Whisk until combined. Add the
mayonnaise and whisk until smooth. Refrigerate until cold. Stir well when ready to serve.
In a large pot of water, cook potato slices until they are tender when
pierced with a fork. Drain well and set aside.
In a medium size mixing bowl, whisk beer, lime juice, flour, cumin and
garlic together until well blended. Let the batter stand at room temperature for 1 hour.
In a large frying pan, heat oil to a depth of two inches. Dip the potato
slices in the batter. Fry in batches in the hot oil until golden brown
about 3 minutes.
Remove the potato slices from the skillet and drain on paper towels.
Sprinkle with sea salt to taste.