If you remove all the seeds and membranes from the jalapeño peppers, the green sauce will only be mildly spicy. The good thing is that if you find it too spicy, you can always add a bit more mayo, sour cream, or Greek yogurt to tone it down. Aji Amarillo paste is quite spicy so if you are adding it to the sauce, and you're sensitive to heat, add only 1 teaspoon.