Notes from the cookbook: You can grill half a pound of shrimp on the panini press in about 2 minutes. That is reason enough to have panini-grilled shrimp in your regular weeknight dinner rotation, don’t you think? For these tostadas I first let the shrimp bathe in a chili-lime marinade before they hit the grill. Also grilled on the panini press: the tostada shells. You just brush a little oil on regular tortillas and after a minute or so on the grill they’re toasty, crisp, and ready for toppings. Black beans mashed with garlic (a terrific technique I learned from a Rick Bayless recipe) and sprinkled with queso fresco make a flavorful base to hold the shrimp on the tostada, and an avocado salsa fresca brings a punch of bright, Southwestern flavor to the dish.