Heat the oil in a medium skillet. Add the onions and sauté over medium-low heat until limp. Add the garlic and continue to sauté until the onion is deep golden, stirring frequently, about 15 minutes.
Preheat the oven to 425°F.
While the onions are cooking, peel the sweet potato and cut into small dice. Place in a small mixing bowl and toss with the olive oil.
Arrange the sweet potato dice in a lightly oiled or parchment-lined small baking pan. Bake for 15 minutes, or until just tender and lightly roasted, about 15 minutes. Stir every 5 minutes or so. Remove from the oven when done.
Puree the tofu with the nondairy milk and salt in a food processor or with an immersion blender in its container.
Place the crust on a baking sheet or a pizza stone. Spread the pureed tofu evenly over the surface of the crust with a baking spatula. Sprinkle with the vegan cheese.
Layer the onion mixture evenly over the cheese layer. Scatter the roasted sweet potato pieces over the onion layer, followed by the olives.
Bake for 12 to 15 minutes, or until the crust is golden. Cut into 6 to 8 slices and serve.