Combine hash, corn flakes, parsley, shallot, and garlic in a large bowl. Mix well and shape into 8 patties, about the same width of your slider buns.
Heat oil over medium-high heat in a large non-stick skillet, and cook patties until browned on both sides, about 6 minutes flipping halfway thru.
To assemble the sliders, evenly distribute arugula among the bottom halves of the buns, top with cooked patties, a few pickle slices and sliced tomatoes. Spread the inside of the top bun with mayo, place on top of the slider and eat up!