Fill a medium saucepan halfway with water and bring to a boil. Cook the orzo until al dente -- according to package directions. Strain the pasta through a colander and rinse with cold water to stop the cooking process. Set aside.
Fold a paper towel over on itself and place on a small plate. Dice the pancetta into 1/2" pieces. Heat a small skillet over medium high heat. Add the pancetta and cook until crispy and browned. Remove from heat and use a spoon to scoop the pancetta, draining any fat, and transferring to the paper-towel lined plate. Set aside.
Make the dressing in a small bowl by combining the lemon zest and juice, dijon mustard, garlic, vinegar, olive oil, salt and pepper. Whisk to combine.
In a large bowl combine the orzo, red onion, grape tomatoes, peas, pancetta, chicken, mozzarella cheese and basil. Pour the dressing over the salad and toss to combine. Serve chilled or at room temperature.