If you're making homemade wrappers: mix flour and salt in a bowl. Then add water and oil to bring it together. Roll it up into a small ball and let it rest for 30 minutes. When you're ready to fold the momos, divide into two logs. Split each to ~ 8 pieces. Roll on a lightly floured surface into 3-4 inch diameter. (I forgot the ratio I used for this so please find a recipe for the wrappers online. Sorry!)
For the filling, start by chopping the vegetables. Heat a pan over medium heat and add 1 tbsp oil to it. Add green onion, ginger, and garlic. Cook for 2 minutes.
Add the rest of the veggies and cook until they are soft, so about 5-7 minutes. Then add pepper, red chili powder, and soy sauce. Continue to mix for a minute.
Fill each dumpling wrapper with ~ 1 tbsp of filling. Lightly touch the edges of the wrapper with water to help with folding. Pinch the edges in to bring it together.
Prepare a steamer with enough water and bring the water to a boil. Lightly grease the steamer basket and place the momos inside, leaving space between each one. Steam for 5-7 minutes, but the timing will depend on your wrappers, so follow your intuition. Repeat with the rest of the momos.
For the chutney: boil tomatoes, dry red chilis, and garlic cloves for 10 minutes. In a small processor, process with 1 tbsp sesame seeds, 1 szechuan peppercorn, and salt to taste. Optional: process with some cashews for a creamier texture.