Aji Amarillo fresco or fresh hot yellow chili pepper.

Ají Amarillo, or fresh hot yellow chili pepper is probably the most common variety used to flavor many different Peruvian dishes. Long and aromatic, it's frequently made into a paste before used for cooking. In spite of its name, ají amarillo can also be orange or green. Also known as aji verde.

You may order it on-line already in a paste form.