To make salsa: With a sharp knife, remove skin and white pith from oranges and discard. Working over a bowl, cut orange segments from their surrounding membranes. Stir in onion, lime juice, cilantro, jalapeno and garlic. Season with salt and pepper.
To make chicken: Heat a small skillet over medium heat. Add coriander, cumin and pepper; toast, stirring constantly, until aromatic, about 45 seconds. Transfer to a small bowl and add salt.
Preheat grill or broiler.
Coat the chicken with the spice mixture. Grill or broil on a lightly oiled rack until the chicken is opaque in the center, 4 to 5 minutes per side. Top with the salsa.
Make Ahead Tip: The salsa (Step 1) will keep, covered, in the refrigerator for up to 8 hours.
206 calories;4.0 g fat(1.0 g sat); 3.0 g fiber; 12.0 g carbohydrates; 30.0 g protein; 31.0 mcg folate; 78 mg cholesterol; 7.0 g sugars; 0.0 g added sugars; 279.0 IU vitamin A; 49.0 mg vitamin C; 71.0 mg calcium; 2.0 mg iron; 425 mg sodium; 400.0 mg potassium