Do NOT touch your face while working with the jalapenos - the capsaicin oils can transfer and irritate skin or burn eyes. Discard seeds and any pepper insides, carefully wash cutting board and knife used with jalapenos, then turn gloves inside out as you take them off so as not to touch the outside surfaces, and throw away.
Since my family likes their salsa on the very mild side, I usually use only about 1 teaspoon cayenne. I think it makes for a very mild, but not bland, version - there's a tiny, tiny hint of a kick in there. If you like your salsa with a little more heat, try a full tablespoon (3 teaspoons).
Nutrition information provided as an estimate only.