Sprinkle gelatin over juice in a small saucepan; let stand 2 minutes. Add 2 tablespoons sugar; cook over low heat, stirring until gelatin and sugar dissolve (about 2 minutes). Chill gelatin mixture until the consistency of unbeaten egg white.
Gently fold blueberries and next 3 ingredients into gelatin mixture. Spoon mixture evenly into 2 (1/2-cup) molds coated with cooking spray. Cover and chill until firm.
Combine sour cream, powdered sugar, and poppy seeds, stirring well. Line 2 salad plates with lettuce, if desired. Unmold salads onto plates; top each serving evenly with sour cream mixture. Sprinkle with grated orange rind, if desired.