Turn your gas range to medium heat and toast the pepper by turning it an inch or two above an open flame for about a minute, until it's completely charred on both sides. (If you lack a gas range, you can transfer the chile to a pan and place it over medium heat. Press the chile against the pan for a few seconds, rotate it, and cook until the pepper is charred.)
Moving quickly, transfer the pepper to a glass or stainless steel bowl. Pierce the pepper a few times with a knife, and cover the bowl with plastic wrap. This will create steam, making the pepper’s skin to fall off easily. Remove the plastic wrap, and using a knife, scrape off the charred bits and discard. Dice the pepper, discarding the membrane and seeds.
To assemble the quesadilla, place a corn or flour tortilla on a cutting board. Start by adding a generous handful of cheese, a tablespoon of black beans, a tablespoon of corn, a handful of kale and a few slices of blistered pepper; top with another tortilla.
Place a skillet over medium low heat and add a teaspoon of butter or olive oil. Carefully transfer the quesadilla and cover the pan. Cook on each side until the tortilla is lightly browned and cheese is oozing out the sides, about 5 minutes. Repeat with the remaining quesadillas. Serve with fresh salsa.