Mix in the softened lime sherbet and tequila, if desired. Stir until fully mixed. The mixture should be a pale green color.
Spoon the sherbet, ice cream and margarita mixture into ice pop molds, smoothing and packing tightly to remove any air bubbles. It helps to tap the molds gently on the counter to level them and remove any air bubbles.
Add the sticks and place the ice molds in the freezer for six hours, or overnight, until the ice pops are frozen solid.
Mix the graham cracker crumbs and salt together on a plate or in a shallow dish.
Once the ice pops are frozen, remove them from the molds and allow to sit at room temperature for a few minutes. The outsides of the pops should be lightly softened.
Working quickly, dip the softened pops into the graham cracker and salt mixture, coating both sides. Sprinkle with more salt, if desired, and garnish with lime slices.
Place the crumb-coated pops on a baking sheet lined with wax paper and return to the freezer until the ice cream and sherbet mixture has solidified again. Keep frozen until ready to serve.