serving dishes. The diners can then assemble their own fajitas by topping a tortilla with some of each of the ingredients, ending with a dollop of sour cream, and then rolling it up. TIME-SAVERS: MICROWAVE TIP: Just before serving, stack the tortillas and wrap them in a damp paper towel. Cook at 100% for 1 minute. DO-AHEAD: Since the fajitas are fine served at room temperature, much of the preparation can be done ahead of time. The sauce (Step 5) can be made and the chicken marinated in advance. Just be sure to cook the chicken and warm the tortillas as close to serving time as possible.