It's not very spicy, so Pico de Gallo might be a better description, but it's a salsa.
1 medium sized onion
2ish cloves garlic
1 "bunch" cilantro
I packet ranch dressing mix
a few tablespoons white/rice wine vinegar
You'll also need sharp knives, and a classy, expensive cutting board such as mine.
Chop up your onion, smash the garlic, then chop that as well
Peel, quarter, de-seed and chop up your cucumber