The flavors of Southeast Asiawere the inspiration for thislean, delicious burger, whichhas an alluring floral note oflemongrass and a good dose ofginger, too.
Process 2 shallots, the lemongrass, and ginger in a food processor until finely ground. Transfer shallot mixture to a medium bowl. Using your hands, gently combine shallot mixture, the pork, salt, and pepper (do not overwork meat). Shape into 6 patties (3 to 4 inches in diameter). Refrigerate, covered, until cold, about 1 hour (or overnight).
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 burgers, flipping once, until cooked through, about 5 minutes per side.
Make salad: Stir together remaining shallot, the lime juice, fish sauce, and chiles in a small bowl. Toss together shredded lettuce, the cilantro, and mint in a medium bowl. Add dressing; toss.
Place each burger on a lettuce cup. Top with salad, dividing evenly. Serve with cucumber wedges, if desired.
Thai chiles are small, fresh, red orgreen chiles, and are very hot. For amilder flavor, remove the seeds. Youcan substitute one fresh serrano chile.