Grill or boil eggplants until soft. Let it cool then gently peel the skin off. Cut the stems and then slice the meat into small pieces. Set aside.
In a big bowl, combine onion, tomatoes, lemon juice, fish sauce and cilantro. Add sliced eggplants; gently mix well. Season with salt and freshly ground pepper to taste. Serve with grilled or fried meat/ fish.