Sauté onion in water over low heat, covered for 10 min. Cut the corn kernels from the cobs with a sharp knife.
Add to sauté pan along with squash and sprigs of marjoram. Cook for 5 min., until vegetables are soft and water has evaporated. Discard marjoram. Transfer to bowl. Add tomatoes or peppers, marjoram, and salt and stir well.
Chill before serving.
Servings: