Harissa paste can be purchased online from a variety of sources such as Amazon.com or igourmet.com. Ethnic grocery stores or large chains such as Whole Foods may also carry harissa paste or spice blends.
Harissa is a sauce, spice blend or paste originating in North Africa, specifically Tunisia. The blend is often referred to as Tunisian chili paste and includes chili peppers, tomatoes, paprika, cumin, garlic and olive oil.
Harissa is usually served with couscous or meat, but can be added to any food as a condiment or flavor enhancer. Many cooking websites, such as Saveur.com, provide instructions on how to make harissa at home.