Heat oil in a large nonstick skillet over medium heat until shimmering. Add tortilla strips and cook, stirring frequently, until golden brown and crispy, about 5 minutes. Using a slotted spoon, transfer to a paper-towel-lined plate; season lightly with salt.
Add the diced onion and jalapeno to the skillet and cook, stirring often, for 3-4 minutes until softened.
Reduce the heat to medium-low and add the beaten eggs, and cook by dragging a rubber spatula through eggs to create large curds (avoid stirring), until starting to set but still wet. Fold the crispy tortilla strips and cilantro into the eggs and top with cheese.
Cover the skillet and cook just until the cheese is melted. Divide among warm flour tortillas and top as desired.