Figure[Black to move]

This should be an easy one now. Your typical search for ideas includes a scan for loose pieces and any enemy pieces on the same line. Here those inquiries point to the rook on a1, which is loose and is lined up with the other White rook on d4. Your first choice of attacker on a diagonal is a bishop. In this case Bf6 skewers the two rooks, again winning the exchange after one moves to protect the other.