Put the 1 tablespoon grapeseed oil in a large skillet, and add the coriander, garlic, mustard seeds, and cumin and cook for about 15 seconds. Add the tomatoes and season with salt, and pepper, stirring well. Add the green beans and cook until the beans are crisp-tender, about 8 to 10 minutes. In another pan, add oil and place over medium heat. Add the cubed paneer and fry until golden on all sides, turning frequently. Gently stir into the finished beans and serve immediately.