1. Combine onion, vinegar, 1/4 cup water, sugar, 1/4 teaspoon salt, and jalapeño slices in a saucepan over high heat; bring to a simmer. Cook 1 minute; remove from heat, and let stand until ready to serve.
2. While onion mixture cooks, heat a large skillet over medium-high heat. Coat pan with cooking spray. Add ground beef, chili powder, cumin, garlic, paprika, and remaining 1/4 teaspoon salt to pan. Cook 5 minutes or until browned, stirring to crumble. Stir in oil.
3. Drain onion mixture. Top tostadas evenly with beef mixture, onion mixture, sour cream, and cilantro.
|