Wash the zucchini and plum tomatoes under cool water. Trim and finely dice the zucchini and tomatoes, and add to a large bowl along with finely chopped onion.

Add chopped cilantro (or parsley), lime zest, and lime juice to the bowl.

Drizzle olive oil over the mixture, add salt, chili powder, and ground cumin. Stir gently until all ingredients are combined.

Taste and adjust flavors if needed, adding more salt or lime juice if desired.

Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow flavors to meld.

Serve in a decorative bowl with tortilla chips, grilled meats, or over tacos.