In a medium saucepan over medium-high heat combine the olive oil, onion, garlic, and salt. Cook, stirring regularly, until the onions soften, 3-5 minutes. Add the paprika, garlic powder, and chipotle, and cook for another minute. Stir in the sweet potatoes, cashews, and water, and bring to a simmer. Cook for 5 minutes or so, until the sweet potatoes are tender.
Transfer the mixture to a high-speed blender, add the lemon juice, and blend until completely smooth, 2-3 minutes. Add water a splash at a time to thin consistency if needed. Taste, and adjust seasoning if needed.
*Pickled Serrano Chiles: I keep these on hand at all times! Slice 8 (or more!) Serrano chiles 1/8th-inch thick and place in 2 cups of white vinegar in a Mason jar. Use the chiles w/in a week or two. You can use the vinegar for weeks after that in dressings, on lettuce wraps, and rice bowls.