Make the harissa oil: Mix harissa, salt, and oil. Bring to a light boil, and stir to combine. Transfer to a small bowl or jar and leave to cool.
Heat a frying pan with some oil and fry onions over medium heat until caramelised, approx. 10 minutes.
Add another splash of oil along with garlic, chilli, oregano, and Baharat spice. Cook a further 2 minutes.
Drain chickpeas, reserving the liquid. Drain haricot beans and this time discard the liquid.
Add all the beans to the onion mixture and combine well. Cook over medium heat for 4 minutes.
Remove 1/4 of the bean onion mixture and set aside to use later as a garnish.
Place beans and onions in a blender along with reserved chickpea liquid, lemon juice, 2 tbsp of olive oil, and one ice cube. Blend until smooth. Taste and season with salt and pepper as desired.
Transfer bean hummus to a serving bowl. Generously drizzle with harissa oil. Top with the reserved chickpea onion mixture. Sprinkle with sesame seeds.