Wash the beans in cool water and drain in a colander. Snap off the stem end and either leave whole or cut into desired lengths.
Bring a pot of salted water to a rolling boil. While the water is heating, set up a large bowl of ice water. Add the beans to the boiling water and blanch for 4 - 5 minutes or until crisp tender.
Remove from the water and transfer to the ice bath. Let sit in the ice water for 4-5 minutes or until completely cool. Remove and drain in the colander. Alternatively, you can steam the beans just until crisp tender then transfer to the ice bath, cool and drain.
Pat dry and chill in the refrigerator if not using right away.
Otherwise, heat oil in a skillet, sauté the minced garlic lightly, add the beans and stir. Add the pecans, Parmesan cheese and chili flakes. When warmed through, transfer to a serving dish and garnish with lemon zest. Serve right away.
Instructions for making ahead of time.You can make most of this recipe ahead of time. Blanch the beans, as described above, then store them in the fridge. You can prepare the other ingredients ahead, as well. Grate the Parmesan, chop the pecans, grate the lemon zest and mince the garlic. Then just before serving, you can quickly stir fry the ingredients in a skillet, garnish with lemon zest and serve piping hot!