In a bowl, mix crab, cheese, and onions. Place 5 tortillas in a single layer on two 14"x17" baking sheets. Evenly cover tortillas with crab mixture to within 3/4" of edges. Top each with one of the remaining tortillas. Bake in a 450° oven until cheese melts, and tortillas are lightly browned, 7-9 minutes. Slide quesadillas onto a board and cut each into 6 wedges. Arrange on a platter and garnish with cilantro sprigs. Serve with chili-cilantro sauce. Makes 10 servings. 

Chili-Cilantro Sauce:

Place 4 medium sized fresh Anaheim chiles on a baking sheet and broil 2" from below heat, turning often, until brown and blistered all over, about 5 minutes. Let cool in pan, then pull off and discard skin, stems and seeds. Coarsely chop. In a blender or food processor, smoothly whirl chiles, 1/4 cup dry white wine (or water), 1 medium size shallot, chopped, and 1 Tablespoon lemon juice. Pour into a 2-3 quart pan, and bring to a boil over high heat, stirring, until reduced to 1/3 cup, 5-10 minutes. Return to blender or food processor. Add 1 cup firmly packed cilantro and whirl till smooth. With motor running, slowly add 1/4 cup butter or margarine, until incorporated. Scrape container sides once or twice. Serve warm. 

(Original recipe is from Joanne in Arizona from the World Wide Recipes news list.)