Boil potatoes until fork-tender, then let cool completely. Meanwhile, mix hummus, mustard, garlic and onion together, plus a pinch of black salt, stirring to combine. (Add hot sauce here if you prefer a spicy deviled egg). Taste, adding more Dijon or black salt to taste, then set aside. Once potatoes cool, slice in half long-ways and use a little spoon or melon baller to scoop out a small circle of the potato flesh (this is your “egg”). Spoon hummus mixture into the hole and garnish with paprika or smoked paprika.