Heat oil in a large skillet over high. Add beef, stir until brown for 5 minutes.
Next, add the taco seasoning packet, diced tomatoes, and follow directions on the seasoning packet accordingly. Cook for 5-7 minutes
While the beef and tomatoes are cooking, place the refried beans in a bowl, cover, and microwave until warm. Set aside to serve
Now heat corn tortillas as desired. Either in a sauce pan over medium heat, heat for 30 seconds each side or 2 minutes with 1 tsp of oil for crispier texture
Finally shred lettuce, and prepare tacos. Place the refried beans down first, then beef, lettuce, cheese, and a sauce of your personal preference.