Heat oil in a large, 12-inch skillet over medium-high heat.
Add the tomato, onion, and chiles, and cook. Stir almost constantly until the onions begin to soften and brown, about 7 minutes.
Add the tequila and cook quickly, stirring, until liquid is nearly reduced to a glaze.
Reduce the heat to medium-low, sprinkle the cheese evenly over the vegetables and stir slowly and constantly until just melted – too long over the heat and the cheese will become tough, oily and stringy.
Scoop queso into a warm dish, sprinkle with cilantro, and serve right away. We like dipping chips in this queso, but it's also great over tacos. You can even add a little fire-roasted salsa to the queso and mix it in. YUM!
If you can't find large jalapenos - you can use 2 small jalapenos or 2 large serrano peppers.