Drain the beans, reserving the bean liquid*. Blend the beans with the garlic, olive oil and cumin. (*See recipe notes)
Measure 60ml of the bean liquid and add to the blender. Blend ingredients until smooth. If the mixture is too dry, add tiny splashes of aquafaba to loosen it up. The texture of the bean dip should be similar to hummus. Season to taste with lemon juice, salt and pepper. Transfer to a bowl, cover and refrigerate until ready to serve.
Prepare the confit tomatoes: Cut the tomatoes into large chunks. Place them in a small saucepan with the peeled garlic cloves and a pinch of salt. Pour in enough olive oil to cover the tomatoes and garlic. Bring to a gentle boil, then reduce the heat and simmer for 15-20 minutes or until the tomatoes and garlic are soft and juicy.
Remove from the heat and stir in the harissa. Leave to cool. When cool, strain through a sieve. Keep the tomatoes and oil in separate bowls.
To serve: Pour the white bean dip into a serving dish and top with the confit tomatoes. Drizzle generously with confit tomato oil. Garnish with fresh oregano leaves. Serve with crusty bread, tortilla chips, cracker or vegetable sticks.