Plunge the radishes into a bowl of cold water, to refresh and crisp.
Scoop the watermelon with a melon baller (retro!), or cut into wedges, slicing the flesh off the rind, then chop into fork-sized chunks. Pop these in the fridge while you make the rest of your salad.
Zest the lemon, reserving the zest. Segment the flesh by slicing off the skin and pith, and cutting into each segment at a 45-degree angle to form wedges. Keep the remaining carcass of the citrus to squeeze over the salad. (You’ll find more info on segmenting citrus on page 41.)
To make the ginaigrette, place the mint, dill and parsley stalks in a small saucepan with the vinegar, gin, sugar, salt and 50 ml (1½ fl oz) water. Bring to the boil, cooking for 4–5 minutes, until the booze stops stinging your eyeballs and the liquid reduces a little.
Pop the onion slices in a jar, strain the ginaigrette over them and leave to pickle for at least 15 minutes. There’s no need to pop a lid on top, unless you’re planning on taking this with you for drizzling at a party.
To serve, drain and thoroughly dry the radish wedges. Assemble the cucumber, watermelon and radish in a serving bowl. Add most of the reserved herb fronds from the ginaigrette, together with the olives, lemon segments and chilli flakes, if using. Crumble or cube the feta into fork-sized chunks and scatter over the top. Toss gently to combine, so the feta doesn’t start collapsing.
Garnish with the remaining herbs and pickled onion. Drizzle with a few tablespoons of the pickling liquid and olive oil, then crack over some black pepper to finish.