1. Sprinkle gelatin over water in a small bowl; let stand until softened, about 1 minute. Microwave on High, uncovered, until the gelatin has completely dissolved but the liquid is not boiling, 10 to 20 seconds. Stir the mixture until smooth.
2. Place mango in a blender or food processor. Process until smooth. Push through a very fine sieve into a large measuring cup until you have 2 cups puree. Whisk the mango puree, sweetened condensed milk, and lime juice in a medium bowl. Slowly whisk in the softened gelatin mixture until well combined.
3. Lightly coat eight 6- to 10-ounce ramekins with cooking spray. Divide the pudding among the ramekins. Refrigerate until set, about 2 hours.
4. To serve, run a knife around the inside of each ramekin to loosen the pudding. Dip the bottom of the ramekin in hot water for 30 to 40 seconds, then invert onto a serving plate, holding ramekin and plate tightly together