In small saucepan over low heat, stir together beans and 2 tablespoons of the salsa. Cook, stirring occasionally, until heated through. Keep warm while preparing omelet.
In small bowl, beat together eggs and water until blended. Evenly coat 7- to 10-inch omelet pan or skillet with cooking spray. Heat over medium-high heat 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. Cook until top is thickened and no visible liquid egg remains.
Spread hot bean mixture down center of omelet. Sprinkle with cheese. With pancake turner, fold sides of omelet over beans and cheese. Slide from pan onto plate. Spoon on remaining salsa. Garnish with lemon and lime wedges, if desired.