In a large pan over medium heat, heat the olive oil.
Sauté the onion until slightly translucent, about 5 minutes.
Add the garlic, and cook for another minute.
Add the ground beef.
Stir it around until it begins to brown, and cook all the way through, 5 to 7 minutes. If there’s a lot of liquid, carefully drain it off and return the pan to the heat.
Add the cherry tomatoes (if using), and cook for another 2 to 3 minutes, or until they start to get wilty and some of them begin to burst.
Stir in the taco seasoning, season with pepper, and remove the pan from the heat.
Divide the lettuce evenly among 4 bowls, and top each lettuce pile with the ground beef mixture.
Garnish each salad with the salsa, avocado, and lime, and serve.