Preheat a large heavy bottomed pan over medium. Saute the shallots and garlic for about 5 minutes, until golden. Add the breadcrumbs and toast them by stirring constantly for about 2 minutes. They should turn a few shades darker.
Add the vegetable broth and wine, salt, black pepper and thyme. Turn up heat and bring to a rolling boil and let the sauce reduce by 1/2, it should take about 7 minutes.
Add the chickpeas and capers to heat through, about 3 minutes. Add the lemon and turn off the heat.
If serving with mashed potatoes, place the arugula in a wide bowl. Place mashed potatoes on top, and ladle picatta over the potatoes. The arugula will wilt and it will be lovely. If you are serving solo, just pour right over the arugula.