Mix yeast, sugar, and warm water in a mixing bowl and let sit for 10 minutes. Add salt, oil, and enough flour to make a soft dough. Knead a few times on a floured countertop just till smooth. Let rest for 5 minutes. Divide dough in half. Roll each portion into an 11-12" circle.
Place on a pizza stone or cookie sheet. Poke all over with a fork. Bake at 500° for about 8-10 minutes, or till browned.
Warm the Nutella slightly in a glass bowl in the microwave, then spread evenly over both pizzas (reserve a little bit to drizzle on top).
Top each pizza with half of the sliced bananas, half of the sliced strawberries, and half of the sliced almonds. Drizzle with remaining nutella.
Top with powdered sugar if desired. Serve immediately.