First boil potatoes until soft; drain.
In large sauté pan, cook chorizo until fully cooked and broken up; remove from pan, strain fat and reserve.
Return pan to heat. Add onions and some reserved fat; cook until soft. Then add potatoes, cumin, cilantro, jalapeno and lime juice; cook gently while stirring to incorporate; set aside.
In a clean nonstick skillet, warm chorizo fat, then add eggs and gently scramble stirring with spatula to avoid sticking.
Once eggs are cooked, add potato mix and fold together. Season with salt.
To assemble: Ladle ¼ cup batter in the center of griddle. Using bottom of ladle, quickly spread batter outward in a circular motion to a diameter of about 7 inches. Drizzle ½ teaspoon oil over the top. Leave dosa batter to brown gradually until outer edges begin to look dry, about 2 minutes, cooking on one side only. With a spatula, carefully loosen dosa from griddle. Bottom should be crisp and beautifully browned. Spoon ½ cup potato filling onto top of dosa, centering it as a strip in the middle of the round. Flatten the potato mixture slightly. Using the spatula, fold the sides of the dosa around the filling to make a cylindrical shape. Drizzle with yogurt and salsa verde.
Put rice in a bowl, rinse well. Cover with 4 cups cold water. Put urad dal and fenugreek seeds in small bowl, rinse well. Add cold water to cover. Leave both to soak for 4 to 6 hours.
Drain rice and dal-fenugreek mixtures in separate colanders. Put rice in a blender. Add 1 cup cold water and grind to a smooth paste. It will take about 10 minutes. May be necessary to work in batches. Repeat the process with the dal-fenugreek mixture.
Combine two pastes in a medium mixing bowl. Whisk together, adding enough water to obtain a medium-thick batter. It should be about 6 cups. Cover bowl with kitchen towel; set in a warm place. Let ferment until surface is bubbly, about 8 hours. Stir in salt, set aside.
Line a broiler pan with foil. Arrange tomatillos on foil along with chile peppers. Broil until charred on top, about 3 minutes. Use tongs to turn; broil other sides until charred, 3 to 4 minutes.
Wrap tomatillos and chiles in foil; let them rest 10 minutes. Unwrap tomatillos and chiles; peel skin off poblano chile and remove seeds. The tomatillos and serrano chile don’t need to be peeled or seeded.
Place tomatillos and chiles into blender and process. Add garlic, sugar and salt. Pulse mixture until ingredients are coarsely chopped.
Add 5 to 6 tablespoons water, onion and cilantro. Pulse quickly until a coarse puree forms; then transfer salsa to bowl.