Cut the kumquats in half lengthwise and remove any seeds.
To a food processor, add the kumquats, fish sauce, chili, and juice of 1 lime. Process until very juicy and saucy, it's OK if it's not completely smooth.
To a bowl, add the pomelo, shallots, peanuts, cucumbers, and cilantro. Toss with the dressing. Taste, if it's not tangy enough, add more lime. If it's too bitter, add a bit of sugar.
Serve topped with crispy shallots.
