1. Preheat oven to 350°.
2. Place potato in a saucepan; cover with water. Bring to a boil. Reduce heat, and simmer 20 minutes or until tender; drain. Cool. Peel potato; thinly slice.
3. Combine 2 teaspoons chives, 1/4 teaspoon salt, pepper, eggs, and egg white in a bowl; stir with a whisk until blended.
4. Heat 1 tablespoon olive oil in an 8-inch ovenproof nonstick skillet over medium heat. Add garlic and potato slices; cook 30 seconds, gently turning potato to coat with oil. Sprinkle with remaining 1/2 teaspoon salt. Press potato mixture with a spatula into a solid layer in bottom of pan. Pour egg mixture over potato mixture; cook 1 minute. Gently stir egg and potato mixture. Press potato back down into bottom of pan; cook 2 minutes. Remove from heat. Sprinkle with cheese.
5. Bake at 350° for 7 minutes or until center is set. Remove from oven. Drizzle with 1 teaspoon extra-virgin olive oil. Loosen sides of tortilla from pan; gently slide onto a serving platter. Cut into 4 wedges. Top with tomatoes and remaining 1 teaspoon chives.