In a bowl, mix the ingredients for Chipotle Lime Mayo. Place the mayo in the fridge until it is ready to use.
Lather you skirt steak with oil and season thoroughly with salt, pepper and garlic. Let rest for 5 minutes in the fridge.
Preheat your fire to a high temperature of 400F.
Add your steak to the grill and cook for about 3 minutes per side or until the internal temperature is 120F.
Once done, pull off and let rest for 5-6 minutes. When done resting, slice the skirt steak against the grain into small pieces.
Re-setup your grill to cook using a cast iron skillet or flat top griddle at a high temperature of about 400F. Add a little oil to the griddle to preheat.
Add a handful of cheese onto the griddle to caramelize. Cover the cheese with a tortilla.
Once the cheese is stuck to the tortilla (about 1 minute), flip it over and lay cheese down to caramelize on the opposite side.
Add more cheese to one half of the tortilla along with the chopped steak, red onions, jalapenos, cilantro and a drizzle of Chipotle Lime Mayo. Let cook for 15 more seconds then carefully flip the empty side of the tortilla onto the full side.
Cook until the outside is crispy and the cheese is melted in between (about 1-2 more minutes). Flip over as needed to prevent burning. Once done, pull off and rest for 2 minutes.
Slice quesadillas into portions and enjoy!