Trim the green beans and cut them crosswise at 1/4 inch intervals (this means to score them, not cut them in teeny bits).  Put the ginger and garlic in a blender with 1/2 C water and whirl till fairly smooth.

Heat oil in a wide, heavy saucepan over a medium flame.  When hot, put in the cumin.  5 seconds later, add the crushed chili.  When it darkens (this doesn't take long), add the ginger-garlic paste and cook for about a minute.  Add coriander, stir a few stirs, add tomatoes and cook for 2 minutes, smooshing steadily.

Add beans, salt, and 1 cup water, bring to simmer, cover, and cook over low heat for about 10 minutes, till beans are just tender.  Uncover.  Add lemon juice, roasted cumin and a whole lot of pepper.  Turn heat up and boil till all liquid is gone, stirring gently.