How to Make It
Place bread in a mini food processor; process until large crumbs form. Combine bread, beef, lamb, 2 tablespoons onion, next 5 ingredients (through egg), 1/2 teaspoon salt, and 1/4 teaspoon black pepper in a large bowl; mix gently until just combined. Shape mixture into 12 (1-inch-thick) patties. Heat a large nonstick skillet over medium-high heat. Add 1 teaspoon oil to pan; swirl to coat. Add patties to pan; cook 2 1/2 minutes on each side or until done.
Combine yogurt, remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, cucumber, and remaining 3 tablespoons onion in a medium bowl, stirring well.
Cook rice according to package directions. Add remaining 2 teaspoons oil and paprika to rice; toss gently to combine.
To assemble, arrange lettuce leaves on a large serving plate; top evenly with rice, patties, and yogurt mixture.