In a sauté pan over medium high heat blister all sides of chilies de arbol. Transfer to a blender and add first amount of pepita seeds. Blend on high until mixture is ground. Set aside.
Heat oil in same sauté pan. Add onions and cook until translucent. Add tomatoes and good until softened.
Place tomato mixture in blender with ground chilies and pepitas. Add orange juice, oregano, salt and ancho chile. Pulse until coarsely ground. Hold refrigerated for service.
For service garnish with cilantro and chopped pepitas.
