1. Halve and peel the avocado and cut into chunks. Place in a blender with the cottage cheese, lime juice, chives and red pepper flakes; blend to the desired consistency. Refrigerate the guacamole 2 hours.
2. Just before serving, preheat the oven to 400°.
3. Brush the tortillas lightly with oil. Cut each tortilla into 8 triangles and place on a baking sheet. Bake the tortilla triangles 5 to 6 minutes, or until browned and crisp. If the tortillas begin to curl, lay another baking sheet on top of them.
4. Line a serving bowl with lettuce leaves and mound the guacamole on top.