To make the spicy quesadillas, first place the large chilies under the broiler for 5-8 minutes until the skin turns black. Let cool in a plastic bag. Remove skin and seeds, cut in half and slice chilies into thin strips.
Place fillets in a deep bowl. Mix mustard and honey and pour in. Toss meat in it so it is coated on all sides. Cover and refrigerate for 1 hour. Then slide under hot broiler (about 4 minutes per side) until meat is cooked. Let cool and cut into thin strips.
For the salsa, combine onion, tomatoes, chilies, cilantro and lime juice in a baking bowl. Add more lime juice to taste, if necessary. Set aside to allow the flavor to develop.
Lightly grease a large heavy skillet and heat moderately.
Place a tortilla in the skillet and sprinkle with a quarter of the cheese. Place half of the scallions, grilled chilies, meat strips and chili strips on top. Sprinkle with a third of the remaining cheese and place another tortilla on top.
Brush with a tiny bit of oil and flip the quesadilla over. Continue frying for a few more minutes until the cheese has melted and the underside is golden brown and crispy. Transfer to a plate and keep warm.
Do the same with the other tortillas and serve the spicy quesadillas.