Boil water in a medium saucepan over high heat. When water is boiling, add the potatoes and carrots. Cook until tender, about 12 minutes. When they are ready drain in a colander and reserve the cooking water. Combine cooked potatoes and carrots, ½ cup of the cooking water, nutritional yeast, vinegar, and salt in a blender.
While the potatoes and carrots are cooking, heat one tablespoon of oil in a saucepan over medium-high heat until shimmering. Add onion and jalapeno and cook until softened and lightly browned, 3 to 5 minutes. Stir in garlic, chipotle, cumin, and mustard and cook until fragrant, about 30 seconds; remove from heat and set aside.