Mix together the salt and sugar in a medium bowl and add the shrimp. Turn well to coat and cover with plastic wrap and chill in refrigerator for one hour.
Alternatively, let the shrimp stand in the brine at room temperature for about 20 mins. In a separate medium bowl, mix together the garlic, cilantro, jalapeño, lime zest, tequila, triple sec, olive oil, and pepper.
Turn to coat, cover, and place in refrigerator for at least 30 mins, but ideally 1-2 hours. Turn grill to high, skewer shrimp and grill for about 2-3 mins per side.