Cook the pasta according to the label instructions. Drain the cooked pasta and rinse it cold water to avoid further cooking.
Meanwhile heat a cast iron or any heavy bottom skillet and add the oil to it. When the oil heats up, add the sliced onions and just enough salt for the onions.
Mix well and let it cook / caramelize over low heat. It will take about 10 to 15 minutes for the onions to caramelize.
Let the onions cool a bit and in the meantime, chop and prepare the rest of the ingredients.
Chop the roasted pepper into bite size pieces and place it in a large bowl.
Add the caramelized onions, cilantro, cooked pasta, cucumbers to the same bowl and combine.
Drizzle the dressing over the salad and mix gently to evenly combine.
Add the cheese if using and toss and serve at room temperature or cold.