In a small bowl, combine all dressing ingredients and whisk together; set aside.
Heat the oil in a skillet over medium-high heat, add onion and garlic and sauté for 2-3 minutes.
Add the meat and cook, breaking up with the back of your spoon until cooked and no longer pink. Drain any excess grease and add spices. Stir to combine.
To assemble the salads, place 2 c chopped romaine into serving bowls, followed by ground beef and toppings of choice.
Drizzle with dressing, cilantro, green onions, and serve with lime wedges and tortilla chips.