Heat the oil in a large cast iron skillet over medium-high heat. Add the poblano and onion to the skillet and cook, stirring frequently, until soft and lightly browned, 3 to 5 minutes. Season with salt and pepper and add the corn. Stir to combine, remove from heat and squeeze half a lime over the mixture.
Transfer to a plate and wipe the skillet clean.
Heat 1/2 teaspoon of the oil in the skillet over medium-high heat until hot. Add one tortilla and scatter over it a quarter of the cheese, and a quarter of the poblano mixture. When the tortilla turns just golden brown in spots, in 1 or 2 minutes, fold it in half, pressing it with a spatula to flatten it. Fold it in half again and then transfer to a baking sheet in the oven to keep warm. Repeat with the remaining ingredients to make three more quesadillas. Serve the folded quesadillas with salsa and guacamole and fresh cilantro