Bring 1 cup of water to a boil.
Dissolve the lime Jello packet in the boiling water, stirring for about 2 minutes until completely dissolved.
Stir in the cold water, tequila, and triple sec until well mixed.
Pour the mixture into shot cups and refrigerate for at least 2 hours, or until firm.
Before serving, dip the rims of the cups in lime juice and then into coarse salt.
Garnish with lime wedges and serve chilled.