I tend to fall back on this appetizer whenever there's a summer get-together. It takes a lot of chopping but it's easy and forgiving. 

Drain a can of clams, reserving the liquid. Then chop radishes, red onions, carrot, tomatoes (if in season), cilantro, a chile or two and toss with some lime juice a bit of the reserved clam juice. Salt and toss again. Serve with good corn chips or even saltines.

I had some leftover homemade tortillas on hand that were going stale, so I deep fried them to make tostadas and piled on the ceviche.