1 pound lean ground beef 1 teaspoon salt 1 teaspoon pepper 1 teaspoon cumin 1 teaspoon mustard powder ½ teaspoon smoked paprika 2 cups diced onion (about 1 whole onion) 3-4 cloves garlic, minced 1 (10-oz) can Ro-Tel Diced Tomatoes and Green Chiles, drained 12 slices cheddar cheese 12 dinner rolls