Shape masa into 18 golf ball-size portions (about 2 Tbsp. each). Cut sides off a zip-top plastic freezer bag. Line top and bottom of a tortilla press with freezer bag. Place masa rounds in freezer bag, 1 at a time, and close tortilla press to form tortillas. (If you don't have a tortilla press, use a flat plate, skillet, or flat-bottomed bowl, and press masa balls between sheets of wax paper against countertop into flat rounds. To ensure even thickness, press dough rounds once, rotate 180°, and press again.) Gently stack tortillas between layers of wax paper.

Pour oil to a depth of 3 inches into a Dutch oven; heat to 375°.

Gently lower 1 uncooked tortilla into hot oil. Once tortilla rises to surface and begins to bubble, cook 10 seconds. Gently flip tortilla, and lightly press center of tortilla, using a metal spatula, to create a U-shape.Cook 30 seconds or until golden brown. Carefully remove from oil, sprinkle with desired amount of salt, and drain upside down on a paper towel-lined wire rack. Repeat procedure with remaining tortillas. Keep warm in a 200° oven.

Cook onion and next 2 ingredients in 2 Tbsp. hot oil in a large nonstick skillet over medium-high heat 4 to 5 minutes or until softened. Add beef, and cook, stirring often, 8 minutes or until meat crumbles and is no longer pink; drain. Reduce heat to medium.

Return beef mixture to skillet; add tomatoes, chili powder, cumin, and 2 tsp. salt, and cook 4 minutes. Add beer, and reduce heat to medium-low. Cover and simmer 15 minutes. Uncover and cook 3 minutes or until liquid is absorbed. Serve mixture in tortillas with desired toppings.

*If you can't find fresh masa, you may substitute the following recipe: Whisk together 3 cups masa harina (corn flour), 1 1/2 Tbsp. all-purpose flour, 1 1/2 tsp. baking powder, and 1 1/2 tsp. kosher salt. Whisk in 2 1/4 cups very hot water until dry ingredients are moistened. (Add more hot water if needed, 1 tsp. at a time.) Knead 3 or 4 times to make a smooth dough.