Ground Beef Tacos with a Zesty Guacamole

Name: Ground Beef Tacos with a Zesty Guacamole
Ingredients: 2 ripe Hass avocados, halved and seeded; 1/4 white onion, chopped; 1 tomato, chopped finely; 1/4 cup cilantro, minced; 1 lime, juiced, plus more to taste; Salt, to taste; 1/2 white onion, chopped; 1 tomato, chopped; 1 pound ground beef; Dash of chili powder; 3 tablespoons Old El Paso Mexican seasoning; 12 taco shells; 1 head of lettuce, chopped; 1/2 cup guacamole (see above); 6 ounces shredded Mexican cheese blend; One 16-ounce jar mild salsa, preferably Green Mountain Gringo*