Step 1

Heat oil in heavy medium skillet over medium-high heat. Add tomatoes, pepper, onion, and garlic; sprinkle with salt and pepper and sauté until vegetables are soft, stirring often, about 10 minutes. Transfer to bowl. Add tuna and sliced eggs; toss gently to distribute evenly. Season filling with salt and pepper; set aside to cool completely.

Step 2

Spray rimless baking sheet with nonstick spray. Roll out 1 pastry sheet on floured surface to 12x16-inch rectangle. Transfer to baking sheet. Arrange ham over pastry, leaving 1-inch border. Spread filling atop ham, leaving 1-inch border. Brush pastry edges with beaten egg. Roll out second pastry sheet to 12x15-inch rectangle. Place atop filling, pressing on edges to seal. Fold 1/2 inch of bottom pastry edge up over top pastry; crimp edges to seal. Brush top with beaten egg. Cut eight 2-inch slashes in top pastry. DO AHEAD Can be made 4 hours ahead. Cover; chill.

Step 3

Preheat oven to 450°F. Bake empanada uncovered until crust is browned and crisp, about 25 minutes. Slide onto platter.