Mix the dry ingredients together. Rub the brisket with the spice rub. Let it stand at room temperature for an hour while you start the fire. Heat a smoker to 300 degrees. Place the brisket on the coolest portion of the smoker. Smoke for 4 1/2-5 hours or until it is tender. Flip and rotate every hour. Smoke and roast the veggies at the same time. Remove from the smoker and allow to rest for 20-30 minutes. Slice thin.
Smoked Tomato Yogurt
Place the tomatoes on the smoker and smoke for 1 1/2 hours. Char all the green onions over the fire in the smokebox. Remove the tomatoes from the smoker and puree. Place the puree in a small pot over medium-low heat and reduce by 1/2. Cool the paste. Finely chop 1 of the charred green onion. Mix all of the ingredients together and chill until ready to use.
Pickled Red Onions
Mix the onions with salt and allow to sit for 1 minute. Cover with the lime juice and refrigerate for at least 30 minutes before use.
Char the peppers over the fire in the smokebox. The skin should be blistered and blackened, 15-20 minutes. Place the peppers in a bowl and cover with plastic wrap to cool. When cooled remove the skin and seeds from the peppers and julienne. Set aside until ready to use.
Warm the pita bread. Spread the tomato yogurt on the inside of the bread. Fill with brisket, peppers, pickled onion, charred green onion, queso fresco, and fresh oregano. Serve with lime wedges.