To prepare the meat, heat a large skillet over a medium-high heat. Add the beef and cook until no longer pink, stirring occasionally and breaking the meat up with the spoon. Add the garlic and beans and cook for 2 minutes more. Add the chili powder, cayenne and water and stir until well combined and some but not all of the liquid has been absorbed. Remove from the heat and allow the mixture to cool slightly. Meat mixture may be made up to 3 days ahead and stored in an airtight container in the refrigerator.
To make the tomato dressing, in a medium bowl, combine tomatoes (with their juices), oil, lime juice, salt and pepper. Dressing may be prepared up to 2 days ahead and stored in an airtight container in the refrigerator.
Place 2 cups of lettuce on each plate or in a lunch container. Top each serving with 1 cup of the beef mixture then sprinkle with 2 tablespoons of cheese. If making to-go, pack 3/4 cup of the tomato mixture in a separate sealable container and put about 8 chips in a separate bag. Right before eating, pour a portion of the tomato mixture with the liquid on top of each salad, and crush tortilla chips on top.