Another idea for the ripe, red ones is a margherita salad.
Alternate slices of tomato, buffalo mozzarella, and julienned fresh basil leaves.
Top with a drizzle of thickened balsamic vinegar.
If you can't get real mozzarella di bufala, then just use regular water mozz, not the low moisture stuff like you would use on pizza or chicken parm.
Now, if you only have low moisture mozzarella, tomatoes, and fresh basil, slice a baguette in half and smear with garlic butter. Put both halves under the broiler for a moment, then place tomato slices and shredded mozz on top of one half and put back under the broiler to melt the cheese. Top with shredded fresh basil, extra virgin olive oil, red wine or balsamic vinegar, and a tiny pinch of dried savory or oregano and serve as a sandwich.
I love this salad and basil always works with tomatoes. I think cheese is in short supply in Thailand though and I'm not sure if @Yorky could possibly find mozzarella of any sort. But I may be wrong...