Heat sesame oil in a skillet over medium heat. Add tempeh and cook, turning, until golden brown on all sides. Drain and set aside. Combine green onions, cabbage, and bell pepper with lemon juice in a medium bowl. Place one egg roll wrapper on work surface. Arrange 1/8 of the vegetables, about 3 tablespoon, and a strip of tempeh close to the middle of the wrapper. Fold over the corner near you, then the two sides corners. Gently roll toward the far corner. Moisten the edges with water, to seal the roll.
Arrange the rolls in a bamboo steamer, and steam over boiling water for ten minutes. Transfer rolls to serving platter and set aside. Combine all the sauce ingredients in a small saucepan over low heat. Cook 3-5 minutes, or until warmed. Serve sauce and individual bowls for dipping either warm or chilled made ahead.