Combine first 8 ingredients; gently fold in crabmeat. Shape crab mixture into 6 patties; dredge in 1/3 cup breadcrumbs. Cover and chill 1 hour.
Melt butter in a large nonstick skillet over medium-high heat; cook crab cakes, in batches, 3 minutes on each side or until golden brown. Drain on paper towels. Serve on buns with Tartar Sauce and coleslaw.