Does Orthodox theology emphasize "redemptive suffering" as much as Catholicism does? Growing up Catholic I've been taught that "my suffering completes what is lacking" in Christ's sacrifice. Any time that I encounter suffering I should "offer it up." St. Bernadette, Francis of Assisi, and Ignatius of Loyola all suffered excruciating pain—rendering them super saints united to Christ's suffering.

How does suffering fit into the Orthodox spiritual life? Is it emphasized as redemptive as much as it is in Catholicism?
No there isn't any theology that ever says Christ's sacrifice and redemptive work is lacking anything in order to save us. Suffering and death are a natural result of Sin. As a Christian you put to death your earthly members and you crucify the works and desires of the flesh for the love of Christ and of mankind. Assisi and Bernadette are not recognized as Saints in the Orthodox Church.