Partially mash potatoes in a bowl with a fork until they begin to hold together. Add tuna, egg, salt, pepper and 1 teaspoon oil; stir to combine. Shape into four 1/2-inch-thick patties.Advertisement
Heat the remaining 2 teaspoons oil in a medium nonstick skillet over medium-low heat; add the patties and cook until browned on the first side, about 5 minutes. Carefully turn the patties with a wide spatula and cook until golden on the second side, about 3 minutes more.
Note: Chunk light tuna, which comes from the smaller skipjack or yellowfin, has less mercury than canned white albacore tuna. The FDA/EPA advises that women who are or might become pregnant, nursing mothers and young children consume no more than 6 ounces of albacore a week; up to 12 ounces of canned light tuna is considered safe.