Drain peaches, reserving 2 tbsp (30 mL) of juice. Slice peaches in half.
In a large resealable plastic bag or bowl just large enough to hold chicken, whisk coconut milk with curry paste, reserved peach juice, lime juice, ginger and fish sauce.
Make several shallow diagonal slashes in each chicken piece.
Then add to marinade and turn to coat. Refrigerate, turning occasionally, at least 2 hours but preferably overnight.
Preheat oven to 375F (190C) and oil a baking sheet. Place chicken on baking sheet and sprinkle with salt. Roast 25 minutes.
Add peaches and tomatoes and stir into any juices. Roast until chicken is no longer pink inside about 10 to 15 more minutes. Sprinkle with chopped cilantro.