Pound each breast between sheets of plastic wrap to a uniform thickness of 1/2 inch. Spread with mustard.
In a large skillet, melt butter over medium heat. Add chicken and cook 3-4 minutes on each side. Stir salsa and lime juice together and add to skillet.
Simmer gently, uncovered, until chicken is cooked through and sauce has thickened, about 6-8 minutes. Sprinkle with cilantro. Serve with rice or noodles.
2 Chicken breasts (skinned and boned)
1 Dijon mustard
1/2 Prepared salsa
2 Lime juice
1/4 Chopped fresh cilantro