Whisk together the tamari, apple cider vinegar, maple syrup, garlic, and water. Cut the tempeh into cubes and place them in a storage container or a small baking dish that's roomy enough for them all to fit in a single layer. Pour the marinade over the tempeh cubes and transfer them to the fridge. Marinate for an hour, or up to 12. Preheat the oven to 350F. Transfer the tempeh cubes to a parchment lined baking sheet or oven-safe baking dish. Bake the tempeh cubes for 15-20 minutes, or until they're lightly browned and crispy at the edges, flipping them halfway through.
While the tempeh bakes, Rinse the quinoa through a fine sieve until the water runs clear. Combine it with 2 cups of water in a medium sized pot. Bring the water to a boil. Reduce the water to a simmer. Simmer the quinoa for 15 minutes, or until all of the water has absorbed into the grain. Fluff the quinoa lightly with a fork, cover it again, and let it rest for 10-15 minutes.
Combine all of the cilantro dressing ingredients in a blender and blend until they're creamy and smooth. Add an extra splash of water if the dressing is too thick.
Combine the cooked quinoa, tempeh, black beans, onion, corn, cucumber, bell pepper, romaine, and cilantro in a large mixing bowl. Add enough dressing to coat the salad very well (I used about 2/3 of the whole dressing recipe) and mix the salad thoroughly. Serve. Salad leftovers will keep overnight in an airtight container in the fridge.