Step 1

Combine oregano and pepper in a small bowl. Sprinkle evenly over both sides of chicken. Heat oil in a large skillet over medium-high heat. Add the chicken; cook until golden and cooked through, about 3 minutes per side. Remove from the pan. When cool enough to handle, slice each cutlet in half crosswise.

Step 2

Spread pesto evenly over cut sides of sandwich thins. Top the bottom halves evenly with arugula, chicken, roasted red pepper and mozzarella; cover with top halves. Press down lightly.

Step 3

Lightly coat an unheated panini griddle, covered indoor electric grill or large nonstick skillet with cooking spray. Lightly coat both sides of sandwiches with cooking spray. Heat the griddle or grill according to the manufacturer's directions. (If using a skillet, heat over medium heat.) Place the sandwiches on the griddle or grill or in the skillet, working in batches if necessary. If using a griddle or grill, close the lid and grill until the bread is toasted, 3 to 4 minutes. (If using a skillet, place a heavy saucepan or skillet on top of the sandwiches. Cook until the bottoms are toasted, about 2 minutes. Flip the sandwiches; top again with the saucepan or skillet. Cook until the other side is toasted, about 2 more minutes.)