Peel and cube the Russet potatoes, then boil in salted water for about 10 minutes until tender. Drain and set aside.

In the same boiling water, briefly cook the shredded cabbage and sliced onions for 3-4 minutes. Drain thoroughly.

Mash the drained potatoes and add the shredded cheddar cheese, mixing until creamy.

Spread Thousand Island dressing on one half of each tortilla. Layer with mashed potatoes, corned beef, cabbage, and onions. Fold to enclose the filling.

Heat oil in a skillet over medium-high heat. Fry the tacos for about 30 seconds on each side until golden brown.

Remove from skillet and drain on paper towels. Garnish with chopped chives and serve hot.