In 10-inch nonstick skillet, heat 1 tablespoon oil over medium-high heat. Add 1/2 cup onion and 1 teaspoon garlic; cook 2 to 3 minutes, stirring occasionally, until softened. Add chiles, cumin and salt; cook about 2 minutes, stirring frequently, until mixture is bubbly. Stir in stock; cook 2 to 3 minutes, stirring occasionally, until slightly thickened. Remove from heat; cool 5 minutes. In blender, pour mixture; cover and blend on high speed about 1 minute or until smooth. Pour into small bowl; reserve until needed. Wipe skillet clean with paper towel.