1Lightly spray 12 (2-oz) shot glasses with cooking spray; gently wipe any excess with paper towel. In 1-quart saucepan, pour orange juice; sprinkle 1 envelope gelatin evenly over juice to soften. Heat over low heat, stirring constantly, until gelatin is completely dissolved; remove from heat. Stir in tequila. Divide orange juice mixture evenly among shot glasses (about 2 tablespoons per glass). In 9-inch square pan, place shot glasses. Refrigerate 30 minutes or until almost set.
2Meanwhile, in same saucepan, combine pomegranate juice, sugar and water. Sprinkle remaining 1 envelope gelatin evenly over juice to soften. Heat over low heat, stirring constantly, until gelatin is completely dissolved; remove from heat.
3Remove shot glasses from refrigerator (orange layer should appear mostly set). Pour pomegranate mixture evenly over top of orange layer in glasses (about 4 teaspoons per glass). Refrigerate at least 3 hours until completely chilled and firm.
4Just before serving, dip a table knife in hot water; slide knife along inside edge of shot glass to loosen. Shake jello shot out of glass onto plate; repeat with remaining jello shots. Serve each jello shot on top of whole orange slice or serve jello shots with orange slice wedges.