In a mixing bowl, whisk together the tahini, lemon juice, garlic, and salt until paste-like and combined.

Slowly add the water, whisking continuously, until the mixture becomes pourable and slightly runny (similar to a sauce, not thick like hummus).

Stir in the chopped parsley, diced tomato, and cucumber.

Taste and adjust lemon juice or salt if needed.

Serve immediately, or cover and chill until ready to eat.