While you prep, thinly slice the radishes into half-moons—this thin cut exposes more surface area for better crunch and flavor absorption. Finely mince the onion, snip the chives into 1/4-inch pieces using kitchen shears (this is faster and cleaner than chopping), and roughly chop the mint. Measure out the feta cheese and have all ingredients within arm's reach before you start cooking.

Bring a pot of water to a boil and add 1 tsp salt. Add the frozen peas and cook for exactly 5 minutes—frozen peas cook quickly and retain their bright color and tender-crisp texture better than fresh. Drain in a colander and set aside while still warm, as they'll continue to absorb flavors from the dressing.

In a small saucepan, heat the olive oil over medium heat. Add the minced onion and sauté for about 5 minutes, stirring occasionally, until it softens and becomes translucent—this mellows the raw onion bite and releases its natural sweetness. I like using a peppery extra virgin olive oil here because it adds depth that's subtle but noticeable against the delicate peas.

Remove the saucepan from heat and stir in the white wine vinegar—adding vinegar off-heat prevents it from cooking off and ensures bright acidity in the final dish. Pour the warm dressing over the cooked peas from Step 2, then gently fold in the sliced radishes, mint, and chives. The warm peas will soften slightly while still maintaining their structure, and they'll absorb the dressing evenly.

Transfer the salad to a serving dish or individual plates. Crumble the feta cheese over the top and season with the remaining 0.5 tsp salt and the pepper. I recommend tasting before adding all the salt, since the feta brings its own saltiness—you may need less than you think.