For the caipirinha marinade, wash limes hot, dab dry and finely grate the peel. Squeeze the limes. Mix 2 tablespoons sugar, paprika powder, 6 tablespoons oil, lime zest and juice.
For the coffee rub, grind coffee beans, chilli, juniper and 1 tablespoon of sugar very finely in a mortar (or in a universal grinder).
Wash all meat, dab dry and cut separately into thick strips. Mix chicken and pork with the caipirinha marinade and beef with the coffee rub. Chill all meat for at least 1 hour.
Put meat separately on 12 skewers. First, grill the chicken and pork skewers on the hot grill for about 12 minutes. Meanwhile, spread 2 tablespoons of oil on beef skewers and grill them all around for 8-10 minutes. Season with salt.