Dice the Roma tomatoes into bite-sized pieces and place them in a colander. Sprinkle ½ teaspoon of kosher salt over the diced tomatoes and let drain for about 10 minutes.

Finely chop the red onion and soak in a bowl of cold water for 10 minutes. Drain and pat dry.

In a large mixing bowl, combine the drained tomatoes, soaked red onion, and diced English cucumber. Add cilantro, jalapeno, minced garlic, ground cumin, lime juice, and olive oil. Mix gently.

Taste the salsa and adjust seasoning with additional kosher salt if needed. Mix again to incorporate.

Cover and refrigerate for at least 15 minutes before serving to allow flavors to meld.