Special equipment: a blow torch
For the smoked tomato sauce: Place the tomatoes and jalapeno in a pie tin with holes poked in the bottom to allow the smoke to pass through and put it on the grill. Place the wood chips on a sheet of aluminum foil and put it where the charcoal goes on the bottom of a grill. Light the wood chips but do not turn on the gas on the grill or start a charcoal fire. Cover the grill. The wood chips will smolder at a low temperature, 90 to100 degrees F, but will not catch fire, billowing a nice smoky flavor to the produce above. Smoke the vegetables for 20 to 30 minutes for maximum smoky flavor. Roughly chop the tomatoes and jalapeno. (As an alternative to cold smoking, use the chipotle in adobo instead of the jalapeno and increase the smoked paprika to 3 teaspoons when cooking the onions and garlic below.)
Cook the onion and garlic in the oil in a saucepan over low heat until translucent, about 6 minutes. Add the cumin and paprika and cook until fragrant, about 2 minutes. Add the tomatoes and jalapeno and cook until the tomatoes are softened, about 5 minutes. Add the tomato juice and 3/4 cup water and simmer until flavors are blended, about 10 minutes. Cool sauce slightly and puree in a blender until completely smooth. Season with salt.
For the grape tomato pico de gallo: Mix the tomatoes, onion, serrano and cilantro in a bowl. Season with the lime juice and salt.
For the tacos: Toss the zucchini in a bowl with the oil and a good pinch of salt and pepper. Cook on a medium to high grill until slightly softened, about 1 minute per side. Allow the zucchini to cool, then dice into 1/2-inch pieces.
In a small skillet over medium heat, toss the zucchini and corn with 1/2 cup of the smoked tomato sauce until the mixture is hot. Mix in the epazote. Reserve the remaining smoked tomato sauce for another use.
To assemble the tacos: Spread 1 tablespoon of the black beans on each tortilla. Top each with 1/4 cup of the zucchini mixture. Dice the charred avocado and add a small amount to each taco. Top each with 1 tablespoon of the pico de gallo.
When blending hot liquid, first let it cool for five minutes or so, then transfer it to a blender, filling only halfway. Put the lid on, leaving one corner open. Cover the lid with a kitchen towel to catch splatters, and pulse until smooth.
Propane gas torches are highly flammable and should be kept away from heat, open flame and prolonged exposure to sunlight. They should be used only in well-ventilated areas. Follow torch manufacturer's instructions for use.