Divide beef into 6 portions about 2 1/2 ounces each. Top each tortilla with a portion of beef. Using a fork, flatten beef on top of tortilla into an even layer, leaving a 1/2" border. Sprinkle with 1/2 teaspoon burger seasoning; season with a pinch of salt.
In a large skillet over medium-high heat, heat 2 tablespoons oil and swirl pan to coat. Arrange 2 tacos beef side down and press into skillet to flatten with a sturdy spatula or burger press. Cook, undisturbed, until beef is browned and cooked through, 2 to 3 minutes. Flip tacos, top each with a slice of cheese, and cook until cheese is slightly melty, about 1 minute more. Transfer to a baking sheet. Repeat with remaining 4 burger tacos.
Top each taco with burger sauce, pickles, lettuce, onion, and sesame seeds.