Separate crescent dough into four long rectangles; place dough rectangles crosswise in an ungreased 15x10" baking pan; press dough over bottom and barely up sides of pan to form a crust; press dough perforations to seal.
Bake crust at 375°for 14 to 19 minutes or until light golden-brown; remove from oven and cool completely.
Spread beans over crust to within a half-inch of edges; stir together sour cream and taco seasoning mix, and spread this mixture over the beans; sprinkle onions, bell pepper, tomatoes, olives, green chiles, and cheese evenly over sour cream mixture.
Cover and refrigerate at least 20 minutes; cut into squares; serve with salsa.
NOTE: I like to spread the salsa evenly over the seasoned sour cream layer (just before sprinkling on the chopped veggies and cheese) rather than serve it on the side.