Place the dried chiles in a heatproof bowl and pour the boiling water over top the chiles. Let sit for 20 to 30 minutes until the chiles are softened. Reserve chile water. Once chiles are softened, cut top off the chiles and remove the seeds from inside. Add to the bowl of a food processor or blender, along with the chipotle chiles in adobo, garlic and lemon juice. Purée, slowly pouring in the olive oil to thicken the sauce. If desired add 1-2 tablespoons of the reserved chile water to thin the sauce a bit (I did not do this). Season to taste with salt and extra lemon juice. The Harissa will keep refrigerated for a few weeks.