Soak the cashews in boiling water for about 15 minutes. Drain and blend with tofu, lemon juice, and zest until creamy.

Slice the red onions, mix with olive oil, vinegar, lemon juice, sumac, salt, and parsley. Allow to marinate for 10-15 minutes.

Slice tomatoes. Whisk olive oil, minced garlic, and chopped herbs, then coat tomato slices and let sit for 5-10 minutes.

Spread the chilled tofu mixture on one slice of bread, layer with marinated tomatoes, sumac onions, and lettuce.

Optionally add avocado slices. Assemble or serve open-faced.