Wash the green beans and dry thoroughly (to prevent oil from splattering), then trim and discard the ends.
In a small bowl or liquid measuring cup, combine the broth, tamari, ginger, garlic, red pepper flakes, salt, and maple syrup.
Heat a large skillet (or wok) over high heat. Once hot (test it by sprinkling some water in — it should sizzle), add the oil and swirl the pan to achieve a thin layer.
Add the green beans and cook, tossing occasionally, for about 3-4 minutes. The beans will be browned in spots but still crisp. Reduce the heat to medium-high, then quickly add the sauce mixture (it will be steamy). Cook, stirring occasionally, for 3-5 minutes, until the beans are tender with a little crunch (al dente) and the liquid is reduced. Turn off the heat and stir in the sesame seeds (optional).