Reheat bacon according to package directions until crisp; coarsely crumble. Stir together bacon, 1/2 cup cheese, avocado, and salsa; set aside to use as filling. Combine remaining 1/2 cup cheese and cilantro in a bowl.
Whisk together eggs, water, salt, and pepper. Melt 2 Tbsp. butter in a 9" nonstick skillet over medium-high heat. Pour half of egg mixture into skillet, and sprinkle with half of cilantro-cheese mixture. As egg starts to cook, gently lift edges of omelet with a spatula, and tilt pan so uncooked portion flows underneath. Sprinkle 1 side of omelet with half of bacon filling. Fold in half. Cook over medium-low heat 45 seconds. Remove from pan, and keep warm. Repeat procedure with remaining butter, egg mixture, cilantro-cheese mixture, and bacon filling. Serve hot.