1/2 medium red or green sweet pepper, seeded and cut into bite-size strips
1/2 medium onion, halved and thinly sliced
1 fresh serrano pepper, halved, seeded, and cut into thin strips*
2 teaspoons vegetable oil
4 6-inch white corn tortillas
Nonstick cooking spray
1/2 cup shredded Monterey Jack cheese (2 ounces)
2 thin slices tomato, halved crosswise
1 tablespoon snipped fresh cilantro
Light dairy sour cream (optional)
Cilantro and lime wedges (optional)