Tony Rosenfeld

The combination of tuna and olives is reminiscent of a salade niçoise.

Spain's famous piquillo peppers add a sweet-spicy edge to the aioli. Idiazábal, a smoky sheep's-milk cheese from the Basque region, is great with the portobellos. If you can't find Idiazábal, substitute smoked Gouda.

The all-American cheeseburger gets a makeover, courtesy of grilled onions, a spicy-smoky ketchup, and an English muffin "bun."

Asian ingredients—from soy sauce to sriracha—flavor the pork burgers. Wrapping it all up in Bibb lettuce leaves adds a fresh touch.

An Indian-spiced burger that's balanced by a cooling raita (yogurt sauce).