Combine the paprika, cilantro and Chipotle pepper in a pestle or small bowl. Use a mortar or back of a spoon to grind the spice together. Cover the pieces of tuna with the mixture completely. Put in the refrigerator until ready to broil.

Heat the oven to broil.

In the meantime, put one tablespoon of butter into a pan and let it melt on medium heat. Add the onion and shallots in oil, and allow the onion cook until it is translucent, stirring all the while. Add the balsamic vinegar and another tablespoon of butter. Allow the butter to melt into the mixture, and whisk.

Put the tuna into the broiler, broil 3 minutes.

Add the juice of the blood orange to the pan and whisk.

Turn the tuna in the broiler and broil for another 3 minutes.

Meanwhile, add the remaining butter to the pan and whisk until the mixture thickens.

Remove the tuna from the boiler, and slice into thin slices.