Pour lime juice, lemon juice, or water into a plate or shallow bowl. Or rub the rim of the glass with a sliced lime.
In another plate or shallow bowl, add sugar or salt, and set aside. If making colored sugar, pulse sugar in a food processor with the desired amount of food coloring until blended. Pour it onto a plate.
Dip the margarita glass into the liquid, and gently shake off excess. Then dip the glass upside down into the salt or sugar, and twist it around to ensure the rim is completely covered. Gently tap off excess sugar and set aside.
Blend the chopped strawberry, lime juice, tequila, triple sec, simple syrup, and ice in a blender until smooth.
Divide the cocktail between the rimmed glasses, garnish with sliced lime and a strawberry, and serve immediately.