1. Place whole red and green peppers onto a large baking pan or cookie sheet and broil on top rack in oven until very soft and charred on all sides, about 30 to 35 minutes (you will have to flip and rotate the peppers every 10 minutes or so to make sure that you get all sides to blister). Remove from heat and place into a bowl covered tightly with plastic wrap for 10 to 15 minutes (this will help the skins to separate more easily).
2. Peel off the thin skins of each pepper and discard. Cut the peppers in half and remove all of their seeds and stems and discard. (You can use a paper towel to wipe them out, or rinse them with cold water.) Slice the peppers into thin strips, about 1/4 inch wide and place into a separate medium size mixing bowl. Drain excess liquid and set aside.
3. Heat 4 tablespoons of the oil in a large skillet over medium heat for one minute. Add the garlic and cook 1 minute until soft but not browned.
4. Add the crushed tomatoes, salt, pepper, sugar, and paprika or hot pepper flakes (if desired) and cook covered, over medium-high heat, until very soft, about 10 minutes. Uncover and cook over medium heat to cook off most of the excess liquid, about 30 minutes, stirring every 10 minutes to prevent burning and sticking to the pan.
5. Add the pepper strips and the 4 remaining tablespoons of olive oil and mix well. Cover and cook over high heat 7 to 8 minutes, then lower to a medium-low heat and continue to cook, uncovered, until mixture has reduced by a third, an additional 45 minutes.
6. Adjust with salt and black pepper to taste. Serve hot or cold drizzled with olive oil and coriander leaves as a side dish for dinner or as a main meal for lunch.