Cook the corn in a large pot of billing water for about 10 minutes. Drain and plunge into bowl of I've water to stop cooking.

Drain corn and set aside to cool completely.

Dice the bacon and cook in frying pan over medium heat until crispy. Use a slotted spoon to transfer it to a plate lined with paper towel and set aside.

Pour out most of the grease from the pan and then add some oil, the onions, vinegar, sugar and a dash of salt and fry over medium- low heat for about 20-25 minutes stirring frequently. Cook till the onions are caramelized and most of the liquid has evaporated. Remove from heat and set aside.

Take cooked corn on the cob and cut off the kernels and place in a large bowl.

Rinse the black beans and place in the bowl with the corn. Add the onion mixture, cilantro and stir to combine. Season to taste with salt and pepper.

If you're making this ahead of time, cover and put in the fridge. Take salad out 30 minutes before serving. Stir in bacon before serving.