For each quesadilla:

3 slices pastrami, cut into thin strips
3/4 cup shredded Swiss cheese
2 teaspoons pickle relish (dill or sweet)
2 teaspoons brown or whole grain mustard
1 8-inch flour tortilla
1 tablespoon oil
In a bowl, mix together all ingredients except tortilla. Lay tortilla on a work surface and pile pastrami mixture on one half. Fold the other half over.
Heat oil in a skillet over medium. When oil is hot, lay tortilla in the pan and cook until golden brown, about 2 minutes. Flip and brown the other side. To serve, cut into wedges.