In a small bowl, mix the spices in with the vegetable stock. Place the tempeh in a shallow baking dish or pan, and pour the mixture over it. Gently toss to coat. Let marinate for two hours or so.
Heat 1 teaspoon of oil in a pan over medium high heat. Add the tempeh strips and any remaining marinade and for about 10 minutes, flipping the pieces occasionally to brown each side. If the tempeh sticks, add a little more stock or a bit of water. When the tempeh had browned a little on each side, remove from the heat and place in a large bowl. Set aside.
Add the onion pan. Cook for about five minutes, until fragrant and translucent.
Add the peppers and cook until slightly softened, about another 5 minutes. If they stick, add a little stock or water.
Remove the vegetables from heat and add them to the bowl with the tempeh.
In a small bowl, whisk together the remaining olive oil with the agave, lime juice, and cilantro. Pour the mixture over the tempeh and vegetable mixture, gently tossing to coat.
To serve, place the lettuce in a bowl with the tempeh vegetable mixture. Top with the tomatoes. Serve with tortillas, avocado, and hot sauce, if using.