Red pepper flakes make this meal spicy and tend to enhance the all of the separate flavors of the dish. You really only need a healthy pinch for one pound of orzo.
Once you have cooked down your sofrito (or mirepoix, basically the same thing but it's really whatever you decide to use here) hopefully you will have some browning going on in your saute pan. That is good news because once you deglaze with your canned tomatoes all of those brown bits will melt into the filling and flavor it beautifully.
Do we all know how to deglaze or what it means to deglaze? Alright, this is why canned tomatoes work better than fresh. The canned tomatoes are stored in their own juices (not to mention they come pre diced and dicing tomatoes can be the biggest pain in the ass and a real buzz kill to the cooking process.)
When your sofrito is cooked down and you have golden brown crust all over your pan, turn that heat up to high and pour in about a cup to a cup and a half of your canned fruit.
Set the can aside, break out your wooden spoon and start turning and scraping the edges to get all that browned goodness off the sides of the pan and into your, what is soon to be, filling.