To prepare tortillas: mix flour, salt and lard with your hands until crumbly and grainy, and lard fully incorporated. Add about a cup of water, kneading in by hand, just until dough comes together, without overworking. Cover with a damp towel and let rest for 5-10 minutes.
Pull off a golf ball-sized hunk of dough (recovering remaining dough to keep moist) and flatten slightly with your palm. Roll out to a 6" circle.
Heat a griddle or two cast iron pans, one (half) over low-medium heat and the other over medium-high heat. Place first tortilla on cooler side for 30-45 seconds, until it is firm enough to be lifted swith tongs. Flip to hotter side for 3-4 minutes, until bottom browns in places. Flip again on hot side of the griddle to brown the other side of the tortilla, about 1-2 minutes. Tortilla is done when both sides are lightly browned in spots, edges pull away from the pan, and tortilla may puff slightly.
Remove to a tortilla warmer (or wrap well in a slightly damp towel) while you complete cooking all tortillas.
Shell shrimp and season with spices. Sautee quickly in grease or oil until opaque. Put 3-4 shrimp in each taco shell, top with salsa, crema, and a sprig of cilantro. Serve with radish slices, particularly if your salsa is hot, to tamp down the pepper burn!