In a medium bowl, dissolve the yeast and sugar in warm water. Let stand for about 10 minutes.
Add the flour, oil and salt to the mixture and mix until well combined and smooth. Let rest while you make the taco filling.
In a medium skillet, cook the ground beef and drain any excess grease. Add the taco seasoning and water and cook for 2-3 minutes over medium heat until the seasoning is well incorporated. Set aside.
Divide the dough into 8 equal parts. Roll each part into a 6″ circle and then place some of the ground beef in the middle of the circle, being careful not to get it within a half-inch of the edge of the dough.
Add onions, Hunt's Diced Tomatoes and cheese (and any other desired toppings) to each calzone.
Fold the dough in half to make a semi-circle shape and press the edges of the dough together. Use the tines of a fork to press the edges together all the way around the rounded edge of each calzone.
Place the calzones on a greased baking sheet and bake at 400° for 15-17 minutes, or until the edges and tops of each calzone are a light golden brown. Serve immediately with your choice of dip (salsa ranch, ranch dressing, guacamole, etc). Enjoy!