Preheat a large skillet over medium-high heat.
Cut the seitan into long, thin pieces. Ideally the slices should be roughly 1/4" thick, 3" long and 2" wide.
Coat the bottom of the skillet with oil and let it get hot. Dredge half the seitan slices in flour to coat. Add to the pan and cook until lightly browed, about two minutes. Proceed to coat the other slices and repeat. Place the cooked seitan slices on a tray or plate covered with aluminum foil, to keep warm. Do not rise out the skillet or turn the heat off, as you're going to make the sauce in it.
Bring a pot of water to a boil for the green beans.
If there is enough oil left in the seitan pan to saute the shallots and garlic, then do so; if not, add a little oil and saute them for about 5 min, stirring often.
Add the white wine to the sauce and raise the heat to bring to a rolling boil. Add the vegetable broth, salt, black pepper, and thyme. Again, bring to a rolling boil and let the sauce reduce by half; this should take about 7-10 minute.
Add the capers and olives to heat through, about 3 minute
At this point, add the beans to the boiling water and let them cook for 2 min, then strain.
Add the parsley and lemon to the sauce and turn off the heat.
To serve: Make a pile of mashed potatoes. Place the seitan over the mashed potatoes and insert the green beans around the seitan, vertically. Use a ladle to douse everything in plenty of sauce.