Add watermelon, cucumber, red onion, jalapeño, and cilantro to a large bowl.
Ingredients (for 4 servings)
3 cups — watermelon, finely diced and seeded • 1 cucumber, diced (optional but common for crunch) • 1/2 small red onion, finely chopped • 1 jalapeño, minced (remove seeds for less heat) • 1/4 cup fresh cilantro, chopped • 2 tbsp fresh lime juice • 1 tsp lime zest (optional, for extra brightness) • 1/2 tsp salt • 1/4 tsp black pepper • 1 tsp olive oil (optional, for rounding flavor)