Place colcannon in a mixing bowl. Add flour, egg, and salt and mix well.
Heat a bit of olive oil in a frying pan over medium-high heat. Take ¼ cup of the colcannon mixture and form into a patty. Coat the patty with breadcrumbs. Fry colcannon patties for 3 to 4 minutes on each side, until golden brown. Remove from frying pan and place on a paper towel-lined plate to absorb excess oil. Continue until all patties are fried.
Mix mayonnaise and sriracha sauce together. Place a dollop of sauce on each colcannon cake, and top with a pickled jalapeño. Serve hot.