Follow the instructions at the link Griff posted with the following changes for red pastrami:
Follow Chris's suggestions for flat selection and trimming.
For the dry cure use:
1/4 cup Morton Tender Quick
1/4 cup paprika
3 tablespoons freshly ground black pepper
2 tablespoons granulated garlic powder
2 tablespoons ground coriander
1 tablespoon sugar
2 teaspoons granulated onion
Use the best Hungarian sweet paprika you can find.
Follow the curing and turning instructions. Rinse very well and soak as instructed.
For the cooking rub use:
3 tablespoons paprika
2 t sugar
1 teaspoon freshly ground coriander seeds, slightly coarse grind
1 teaspoon granulated garlic powder
1/2 t cayenne
If using a corned beef soak in cold water for a few hours, changing the water twice, dry, then rub with the above cooking rub. You'll get better flavor, imo, from starting with a raw brisket flat but try the corned beef and see hwat you think.
For a deli finish you can add a steaming phase to the end.