The title says it all so here we go!
Me importa un pepino (I care a cucumber)
When you don’t care about something you can mention cucumbers as it means that you simply don’t give a damn!
Estar de mala leche (to be of bad milk)
To be of bad milk means you’re in a bad mood and refers to a temporary feeling.
Es del año de la pera (it is from the year of the pear)
This is used to refer to old objects, especially when something is so old that you can’t remember when you got it. In English, phrases like ‘donkey’s years ago’ would be comparable.
Ser salado (to be salty)
In Spain, ser salado means to be witty, amusing or charming.
Vete a freir espárragos (go fry asparagus)
This is a way of telling someone to go away or leave you alone. A good English equivalent would be telling someone to ‘get lost’.
Estar como un flan (to be like an egg custard)
This means to be nervous about something, like an exam for example. Ser un flan is an equivalent way of saying that you’re shaking like a leaf.
Estar más bueno/buena que el pan (to be better than bread)
This is a great way to talk about someone being attractive or beautiful. Telling someone that they’re better than bread is a real compliment!