Guevara v. Gonzales, 450 F.3d 173 (5th Cir. May 19, 2006) (motions to reopen or reconsider are considered collateral attacks of prior immigration decisions; res judicata bars collateral jurisdictional attack of previous decisions of the BIA to grant or deny motion to reopen).
http://caselaw.lp.findlaw.com/data2/circs/5th/0460685cv0p.pdf