Drain and rinse chickpeas thoroughly, then transfer to a bowl. Mash with a fork until mostly smooth with some pea-sized bits left for texture.

In the same bowl, whisk together vegan mayo, Dijon mustard, and lemon juice. Stir until creamy and tangy.

Add chopped celery and minced red onion to the mixture. Stir gently until evenly distributed.

Sprinkle salt and black pepper to taste. Mix thoroughly, then adjust seasoning as needed.

Toast whole grain slices until edges turn golden brown.

Spread a generous layer of filling on one slice. Top with leafy greens and tomato slices.

Sprinkle fresh herbs over the filling, press sandwiches gently, and cut diagonally.

Serve immediately or wrap for lunch on the go.