‘뭐가 제일 잘 나가요?’
‘잘 나가다’ means that a product sells well. When you want to get recommendations for popular items or menus at a store that sells goods or a restaurant that sells food, you can ask ‘뭐가 제일 잘 팔려요?’ or ‘무슨 메뉴가 제일 잘 나가요?’.
Or, when you want to get a menu recommendation, you can ask ‘메뉴 추천해 주세요’ or ‘메뉴 추천해 주실 수 있어요?’.
‘맵기는 어떻게 해 드릴까요?’
‘맵기’ refers to how spicy it is. Koreans love spicy food, and restaurants that serve spicy food can adjust the level of spiciness. There are usually ‘순한 맛(mild), 보통 맛(normal), and 매운 맛(spicy)’ tastes. ‘순한 맛’ is not spicy at all. It is good for those who are not accustomed to spicy taste. The ‘보통 맛’ is medium spicy, similar to Shin Ramen. The ‘매운 맛’ is very spicy, similar to ‘불닭볶음면(spicy chicken stir-fried noodles)’. Extremely spicy tastes include ‘미친 맛(crazy taste)’, ‘핵폭탄 맛(nuclear bomb taste)’, and ‘지옥 맛(hell taste)’.
So when they ask about the level of spiciness at a restaurant, they ask, ‘맵기는 어떻게 해 드릴까요?’. Then you just tell them what spice you want.
You can also adjust the spiciness level after tasting the food. If it is not too spicy, you can ask for ‘더 맵게 해 주세요(please make it more spicy).' or '더 맵게 해 주실 수 있어요?(Can you make it more spicy?)', and if it is too spicy, you can ask for '덜 맵게 해 주실 수 있어요?(Can you make it less spicy?)' or '물 좀 더 넣어 주세요(Please add some more water)'.
‘라면 사리도 하나 추가해 주세요.’
‘사리’ means a bundle of yarn, string, and the like that are overlapped and wrapped around each other. In Korea, when you eat food, you add noodles to the food and boil it.
Types of saree include ‘라면(ramen)’, ‘당면(glass noodles)’, and ‘우동(udon)’. Additional ingredients other than noodles are referred to as ‘토핑(toppings)’. ‘토핑’ include eggs, cheese, rice cakes, sausages, ham, and fish cakes.