Preheat oven to 375 degrees F. Spray muffin tins with nonstick cooking spray.
Wrap 6 tortillas at a time in a damp paper towel and microwave for 30 seconds. Press tortillas into each muffin cup.
Heat a large skillet over medium-high heat and cook ground beef and onion until beef is browned and onion is tender; drain excess grease.
Season beef with salt, pepper, paprika, garlic powder and cumin. Stir in drained tomatoes and let cook for 2-3 minutes, or until heated through.
Spoon beef mixture evenly (1.5 ounces each) between taco cups. Top each cup with 2 teaspoons of shredded cheese. Bake for 10-12 minutes, or until tortillas are crisp and cheese is melted.
Top with your favorite taco toppings before serving, if desired (log separately).