To prepare salad, heat a large non-stick skillet over medium-high heat. Coat pan with cooking spray. Add beef and garlic, and cook until browned, stirring to crumble. Drain; return beef mixture to pan. Stir in rice through next 4 ingredients (through pepper). Cool slightly. Combine lettuce and next 4 ingredients (through beans) in a large bowl; toss to combine.
To prepare dressing, combine sour cream, salsa, chili powder and cumin, stirring with a whisk. Spoon dressing over lettuce mixture; toss to coat. Place lettuce mixture on plate or in tortilla bowl. Top with rice mixture and shredded cheese.