If using wooden skewers, soak them in water for 10 minutes.
Preheat grill on medium heat.
Alternately thread chicken and peppers onto skewers.
In a medium bowl, whisk together olive oil, lemon juice, lemon zest, garlic, mustard and tarragon. Reserve 1/3 cup of olive oil mixture and set aside.
Oil grill grates. Brush kabobs with some of the olive mixture and place on grill.
Grill kabobs, basting frequently with olive oil mixture and rotating every 3-4 minutes, until chicken is cooked through, about 10 - 15 minutes, or until a thermometer inserted into chicken reads 165 degrees.
Remove from grill. Serve drizzled with reserved olive mixture over your favorite rice or couscous, garnished with lemon wedges, if desired.