Wash the green beans and trim the ends. Slice into fine rounds, 1/8 to 1/4 inch thick. (1-inch long segments also is good.) When all the beans are chopped, set aside in a bowl.
Put the ginger in the blender with 3 Tbsp of water and blend at high speed until it is a smooth paste.
Heat the oil in a 10-inch skillet over medium heat. While it is heating, pour in paste from blender and add turmeric. Fry, stirring constantly, for 2 minutes, then add the sliced green chilies and the parsley, and after another minute, put in the green beans and continue cooking and stirring for about a minute. Add the cumin, coriander, 1 tsp of the garam masala, lemon juice, salt, and 3 Tbsp of warm water. Cover skillet, turn flame very low, and let beans cook slowly for about 40 minutes, stirring every 10 minutes or so.
To serve: these beans can easily be cooked in advance and reheated. Serve them in a warm dish, with 1/4 teaspoon garam masala sprinkled on top. They go well with nearly all meat and chicken dishes. They can be eaten with plain boiled rice and Moong Dal, or served with hot pooris or paranthas or chapatis.