Make lime juice out of limes - you should end up with about 1/4 cup of freshly squeezed lime juice. Pour salt into a small dish. Using a lime wedge, wet the rim of a rocks glass and dip into the salt. In a cocktail shaker, muddle one strawberry. Add the tequila, lime juice, and 1 tbsp agave syrup, and fill with ice. Shake and strain into the glass. Garnish with the second strawberry.