Preheat the oven to 350°F. Lightly grease an oven-proof skillet, then add the cheese. When the oven is ready, place the cheese in the oven and bake until melted, about 15 minutes.
Meanwhile, in a skillet, melt the butter on medium-low then add the jalapeño, onion, and celery. While stirring occasionally, cook until softened. Add the garlic and cook for 30 more seconds.
Stir in the cilantro, salt, cumin, oregano, and cayenne. Stir in the crawfish until well blended with the vegetables, then stir in the lime juice, and Worcestershire sauce. Taste and adjust seasonings. Cook for a minute or just until the crawfish are warmed, then remove them from the heat.
Remove the cheese from the oven, top with the crawfish, then serve immediately with warm tortillas and salsa. Spoon the queso fundido into the tortillas and top with salsa to make your own tacos.