Pour the beans onto a sieve, rinse and place in a bowl. Peel garlic, chop coarsely and add to the beans. Drain the tuna. Put 1/3 of the fish aside for garnishing. Add the rest of the tuna and 4-6 tablespoons of oil to the beans and puree with the cutting stick of the hand mixer. Season to taste with lemon juice, salt and pepper.
Wash, clean and slice the tomatoes. Put 1 tomato slice in each spoon or bowl. Add a heaped tablespoon of bean purée. Garnish with the rest of the tuna and thyme, drizzle with 1 tablespoon of oil. Grind pepper over it. Serve the rest of the bean purée extra