Blend all the ingredients under marinade in a small blender until smooth.
In a large bowl, add the sliced veggies. Add half of the marinade and toss well. In another bowl add the beans and the remaining marinade and toss well. Let sit in the refrigerator for 15 mins to half an hour.
Heat a skillet over medium high heat. Add a tsp of oil. Remove veggies from the marinade and add to the skillet. Cook until tender. Add a dash of chipotle pepper powder for smokyness towards the end. Cook a min longer to sear the veggies. Transfer to a bowl.
Transfer the beans and the marinade into the same skillet. Add any leftover marinade from the veggie bowl as well. Cook over medium heat until the marinade thickens. Taste and adjust salt and spice.
Assemble the fajita tacos with warmed tacos or tortillas, generous helping of the grilled veggies and sizzling beans. Add some salsa, avocado slices or guacamole, a dash of black pepper, and lemon juice. Serve hot!