For momo:

get some ground meat of your choice

add salt to taste, chopped onion and cabbage, green onions, garlic, ginger

also add dalchini and sukumel. if you can get meat masala from indian store then add it. if you cant get it then add ordinary cooking masala. you can add either butter and some water or you can add chicken cubes found in grocery stores. the best stuff to make momo juicy is animal fat and thats what they use in kathmandu but you cannot find it here. sounds gross and unhealthy but tastes good!

make sure you add some oil in boiling water in pot which will make your momo juicy and also help momos not to stick on the pan.

For achar:

fry onions in oil and and fry and cook tomatoes. add salt, chilli, garlic and ginger. make sure you cook it good untill it looks like paste. fry some seasme seed "til" in a pan.be cautious not to burn them as it will ruin your achar. mix the tomato achar and roasted sesame seed in grinder and add some chopped cilantro and your achar will be ready. you can add either timmur or sesame seed but not both.

lemme know how it goes.