Whisk garlic, olive oil, red wine vinegar, tequila and lime in a small measuring cup. Place chicken in a flat baking dish (I used an 11×7 glass baking dish) and pour marinade overtop. Let marinate for 1 hour at room temperature or you can cover and refrigerate for up to 4 hours.
Preheat the grill to medium. Thread vegetables and chicken on stainless steel skewers. Brush with tallow, lard or ghee (this prevents the vegetables from sticking and helps the outside caramelize). Grill skewers 2-3 minutes per side until vegetables are golden on the edges and chicken is cooked through.
Whisk all of the sauce ingredients together and serve with kabobs.