Place the steak in a Ziploc bag. In a mortar (or using the blade of a knife on a cutting board), mash minced garlic to a paste. Add chili powder, cumin, Worcestershire sauce, sugar, pepper, allspice and olive oil. Blend well, pour over steak, seal, and turn to coat. Marinate at room temperature up to 1 hour, or overnight in the fridge. Bring meat to room temperature before proceeding.
Combine cucumber, tomato, scallions, lime and ginger. Add salt and pepper to taste, and set aside.
Prepare charcoal or gas grill. Sear steaks and cook 3 to 5 minutes per side for medium rare. Rest steaks wrapped in foil for 10 minutes before slicing. (This ensures juicy meat and crisp lettuce cups.)
Arrange lettuce leaves on a platter. Slice steak thinly on the diagonal and divide over lettuce leaves. Top with a spoonful of gingered salsa and chopped peanuts.