In a bowl, whisk eggs; set aside 1 tablespoon of eggs. Combine the spinach, feta cheese, garlic, pepper and remaining beaten eggs.
Unroll pizza crust; roll into a 12-in. square. Cut into four 6-in. squares. Top each square with about 1/3 cup spinach mixture. Fold into a triangle and pinch edges to seal. Cut slits in top; brush with reserved egg.
Place on a greased baking sheet. Bake at 425° until golden brown, 10-12 minutes. If desired, serve with tzatziki sauce.