4 tablespoons (about) butter
FOR CAKES: Mix first 8 ingredients in large bowl. Mix in enough breadcrumbs to form stiff mixture. Shape mixture into sixteen 1/4-inch-thick patties. (Can be prepared 8 hours ahead. Cover and refrigerate.)
FOR SAUCE: Combine rice vinegar, sugar, lime juice, water, red pepper, garlic and sesame seeds in small bowl; stir until sugar dissolves. Mix in cucumber. Let stand 30 minutes at room temperature to allow flavors to blend.
Preheat oven to 250°F. Melt 1 tablespoon butter in heavy large skillet over medium heat. Working in batches, add crab cakes and cook until golden, about 4 minutes per side, adding more butter to skillet as necessary. Transfer to paper towels; drain. Transfer to baking sheet; keep warm in oven. Divide crab cakes among 8 plates. Spoon sauce around cakes.