In a mixing bowl, whisk together the vegan yogurt, Dijon mustard, agave, lemon juice and zest, olive oil, soy sauce, minced garlic, nutritional yeast, smoked paprika, onion powder, oregano, thyme, salt, and pepper until the mixture is smooth and well combined. Reserve about 2 tablespoons of the marinade for later use.

Carefully unwrap the super firm tofu and pat it dry using a clean kitchen towel. Cut the tofu into bite-sized chunks, typically about 1-inch pieces.

Place the tofu chunks into the bowl with the marinade and gently toss to coat each piece thoroughly. Allow the tofu to soak in the flavors for at least 15 minutes at room temperature.

While the tofu marinates, preheat a large skillet over medium heat. Add a small drizzle of olive oil to the skillet.

Thread the marinated tofu onto skewers if desired. Place the skewers in the hot skillet and cook for about 3 minutes on each side until golden-brown.

Once the tofu is browned, toss with the reserved marinade. Warm the pita bread in the skillet for about 30 seconds on each side. Spoon the tofu into the warm pita and drizzle with Vegan Tzatziki.