In a large skillet over medium-high heat, heat the olive oil for about 1 minute. Add the onion and garlic. Cook for 2 minutes, until tender.
Add the bell pepper, jalapeño pepper, and 3 ounces of diced tomatoes to the skillet. Cook for 3 to 4 more minutes.
Transfer the mixture to a large bowl. Set aside. Reserve any liquid left in the skillet and place back over the heat.
Add the ground beef to the skillet. Cook for 8 to 10 min¬utes, crumbling the meat, until browned.
Add the cumin, paprika, salt, and pepper. Stir to combine.
Transfer the beef to the large bowl with the onion and pepper mixture. Toss to combine.
Mix in the remaining 3 ounces of tomatoes.
Gently stir in the avocado. Do not overmix.
Plate each serving of taco salad with a portion of the romaine, cheddar cheese, sour cream, and cilantro toppings.