Remove the seeds and stems from the dried chiles and add to a small pot with about 1 cup of water and bring to a boil for 8 minutes.
Add the olive oil to a large frying pan and then add the onion and the garlic and saute for about 3 minutes.
Add the tomatoes and the peppercorns and continue sauteing for 5 minutes.
Add the chiles that have been boiled and then add 1/2 cup of water and bring to a boil, let simmer over medium heat for about 5 minutes.
Add the above ingredients to a blender and blend until smooth. Strain and set aside the resulting sauce.
In a large stockpot, add 8 cups of water with salt and cumin. Bring to a boil and add the carrots and cook for 10 minutes. Add the potatoes and continue cooking for 10 minutes longer.
Add the sauce from above, the crab legs and cook for 15 minutes longer.
Add the shrimp and the celery and cook for 15-20 minutes. Add additional salt to taste.
Enjoy with limes and tortillas.