A dollop of bright, smoky pineapple salsa tops the burgers,which are spiced with toastedcumin and coriander andcapped by sprigs of freshoregano to evoke the far sideof the Mediterranean.
Toast cumin seeds and coriander seeds in a dry small skillet over medium heat, shaking pan often, until seeds are just beginning to brown, about 1 minute. Let cool. Finely grind seeds in a spice grinder. Pour through a fine sieve into a small bowl; discard any coarse pieces. Stir in salt, pepper, and dried oregano.
Process salsa in a food processor until smooth. Using your hands, gently combine salsa, spice mixture, and lamb in a large bowl (do not overwork meat). Shape lamb mixture into 14 patties (about 2 inches in diameter and 1/2 inch thick). Refrigerate patties, covered, until cold, about 1 hour (or overnight).
Using a 2-inch round cookie cutter, cut the centers out of top and bottom halves of buns.
Preheat grill to medium-high (if using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 3 to 4 seconds). Brush grill and burgers with oil. Grill, flipping once, 3 minutes per side for medium-rare. Toast buns, cut sides down, on grill during the last minute of cooking, if desired. Serve burgers on buns. Top with salsa; garnish with fresh oregano, if desired.