Preheat grill to 300 to 350 (medium) heat. Grate zest from lime to equal 1 tsp.
Cut lime in half; squeeze juice from lime to equal 3 Tbsp.
Combine chicken, lime zest, lime juice, 1/4 cup olive oil, and next 3 ingredients.
Let stand 10 minutes.
Remove chicken from marinade, discarding marinade.
Grill chicken, covered with grill lid, 5 to 7 minutes on each side or until done.
Prepare pasta according to package directions.
Combine vinegar, mustard, and remaining 1 Tbsp. olive oil. Toss orzo, bell pepper, cucumber, and dill with vinegar mixture. Season with salt and pepper to taste.