Sauté the onions: Heat olive oil in a large sauté pan on medium high heat. When the oil is shimmering, add the onions. Sprinkle with a little salt and sauté for 2-3 minutes, until the onions just begin to color.
Add the peppers: Add the peppers and stir well to combine with the onions. Sauté for 4-5 minutes, stirring often. The peppers should be al dente—cooked, but with a little crunch left in them.
Add the garlic: Add the garlic, and sauté another 1-2 minutes.
Add salt, sugar, oregano: Sprinkle a little more salt over everything and add the sugar and dried oregano. Cook 1 minute.
Add the diced tomatoes: and cook just one minute further.
Add basil, black pepper, lemon juice: Turn off the heat and mix in the torn basil. Grind some black pepper over everything. Right before serving squeeze a little lemon juice over the dish.
