Put the potato pieces in a large skillet and cover with water. Bring to a boil, then reduce the heat to medium and simmer 3 minutes. Pour out all but about 1 tablespoon of the water.
Add the olive oil, scallions, garlic and chili powder to the skillet and cook, stirring, 2 minutes. Add the bell peppers and 1/2 teaspoon salt and cook, stirring occasionally, until the potatoes and peppers are tender, 5 to 7 more minutes. Add the tofu and 2 tablespoons water and cook until the tofu is heated through, about 3 more minutes. Season with salt.
Warm the tortillas in a skillet or in the microwave. Divide among plates and top with the tofu scramble. Pile the cheese, cherry tomatoes and lettuce on top.
Photograph by Antonis Achilleos
Recipe courtesy Food Network Magazine