2 tablespoons olive oil
2 tablespoons fresh lemon juice
1 tablespoon honey
2 beets, boiled, peeled, cut into 1/3-inch cubes
1 large orange, peel and pith cut away, flesh cut into 1/3-inch cubes
1 cup chopped red onion
1/4 cup chopped pitted green Greek olives
1 large shallot, minced
2 tablespoons chopped fresh cilantro
1 jalapeño chile, seeded, minced
1 garlic clove, minced
1 1/4 teaspoons salt
3/4 teaspoon ground black pepper
1/2 teaspoon paprika
1/2 teaspoon ground cumin
1 3/4 pounds ground lamb
Nonstick vegetable oil spray
4 large cracked-wheat hamburger buns, split horizontally
1 1/3 cups thinly sliced Bibb lettuce
Mayonnaise