In small bowl whisk together eggs, water, salt and pepper. In an 8 - inch skillet saute mushrooms and garlic in 1 teaspoon olive oil until mushrooms are golden brown, stirring occasionally. Stir in sun dried tomatoes. Remove mixture from skillet; keep warm.
Heat same skillet over medium - high heat. Add remaining oil to skillet. Add egg mixture and reduce heat to medium. Immediately begin pushing the eggs from edge to center of skillet until mixture resembles small pieces of cooked egg surrounded by liquid egg. Stop stirring. Cook 30 to 60 seconds more or until egg is set and shiny.
Spoon mushroom mixture on top half of omelet; add fresh spinach leaves. Sprinkle with shredded Italian cheeses. Using a wide spatula, fold omelet in half. Transfer to dinner plate and sprinkle with feta cheese. Serve immediately.