To soften store bought tortillas, fold a sheet of wax paper in half; place tortillas in side. Fold open edges up to seal packet. Microwave on high 15 to 35 seconds.

Place 2 roast beef slices on each tortilla. Sprinkle cheese evenly down center of each filled tortilla. Roll up tortilas, enclosing filling. Place each filled tortilla diagonally in center of a sheet of wax paper over tortilla. Roll tortilla toward corner of wax paper. Place seam-side-down on a microwave-safe plate. Microwave 2 tortilla roll-ups on High until cheese is melted, 1 1/4 to 1 1 /2 minutes.