Cut the seitan into narrow strips about 2 inches in length. In a mixing bowl, gently toss with the lime juice, olive oil, and chili powder
Heat the oil in a large skillet and add the seitan mixture and bell pepper strips. Turn the heat up to medium high and cook, stirring often, until the seitan is sizzling hot and the bell peppers are tender-crisp, about 5 minutes.
Place the lettuce, tomatoes, salsa, and/or picante sauce in separate serving bowls.
Distribute two warmed flour tortillas to everyone.
To assemble the fajitas, have everyone place a few strips of the seitan and peppers mixtures in the center of their tortillas and garnish them as they wish. Fold one side of the tortilla over the other and pick up to eat out of hand.