Grate 1 of the limes until you have 1 teaspoon of zest.
Juice the limes and measure out 3 tablespoons of juice.
Mix the lime zest, lime juice, mayonnaise, cilantro, taco seasoning, and salt in a bowl until evenly combined. Taste and add more mayonnaise if you like it creamier.
Place the coleslaw mix in a bowl and scoop the dressing onto it.
Toss well to mix.
Serve cold. Refrigerate leftovers for up to 5 days.