What does pica mucho mean at a taquería?

That it is very spicy, not that it is warm: picar is to be spicy hot, and temperature is está caliente. La taquería is the taco place, el taquero the person making the tacos, el trompo the vertical spit, con todo with everything, and el refresco the soft drink.

Words at the taquería

la taquería
the taco place
el taquero
the person making the tacos
el trompo
the vertical spit
con todo
with everything (onion, coriander, pineapple, salsa)
picar
to be spicy hot
el refresco
the soft drink
Verde, pero poquita. Pica mucho.

Green, but just a little. It's very hot.

¿Cuánto le debemos?

How much do we owe you?

More about Tacos al pastor