In small bowl, beat together eggs and water until blended. In 7 to 10-inch omelet pan or skillet over medium-high heat, heat butter until just hot enough to sizzle a drop of water. Pour in egg mixture. (Mixture should set immediately at edges).

With an inverted pancake turner, carefully push cooked portions at edges toward center so uncooked portions can reach hot pan surface, tilting pan and moving cooked portions as necessary. When top is thickened and no visible liquid egg remains, sprinkle with chilies and cheese.

Place tortilla on plate. With pancake turner, carefully slide egg onto tortilla. Fold tortilla and egg in half, then fold in half again. Garnish with cilantro and serve with salsa, if desired.