Heat a skillet over medium-high heat, add chorizo, and cook until chorizo is crisp
Add chopped onions to remaining oil and cook, stirring occasionally, until onions are soft ( 7-8 mins)
Add tomatoes and cook until they begin to fall apart ( 3-4 minutes)
Add clams and reserved chorizo to pan; cover with lid tightly and cook until clams open ( 9-10 mins)
Remove lid and discard any unopened clams.
Season to taste with sea salt and cracked black pepper
Serve!