Slice cucumbers and place in a colander.

Sprinkle cucumbers with salt and toss.

Place the colander over a bowl and refrigerate for 40-45 minutes to drain liquid.

Shake excess moisture from the cucumbers.

Transfer cucumbers to a large bowl.

Add diced tomatoes and onions to the bowl.

In a separate bowl, whisk together lemon juice, cider vinegar, olive oil, Dijon mustard, sugar, dill weed, black pepper, and cayenne pepper.

Pour the dressing over the salad mixture and toss to combine.

Taste and add salt, if necessary.

Garnish with crumbled feta cheese, if desired.