Combine first 6 ingredients in container of an electric blender or food processor; cover and process until smooth.
Place chicken in a heavy-duty, zip-top plastic bag. Add 1/4 cup tomato sauce mixture, reserving remaining tomato sauce mixture. Seal bag, and shake until chicken is well coated. Marinate in refrigerator at least 15 minutes.
Remove chicken from marinade, discarding marinade. Coat grill rack with cooking spray, and place on grill over medium-hot coals (350° to 400°). Place chicken on rack; grill, covered, 5 minutes on each side or until done. Serve with reserved tomato sauce mixture. Garnish with fresh jalapeno slices, if desired.