foreach (string fieldName in new List<string>(){"Name","Start","Finish"});
{
  ctx.Load(ctx.Tasks,c => c.Include(t => t[fieldName]));
}
ctx.ExecuteQuery();

foreach (string fieldName in new List<string>(){"Name","Start","Finish"});
{
    ctx.Load(ctx.Tasks,
    c => c.Where(t => t.IsSummary),
    c => c.Include(t => t[fieldName])
    );
}

ctx.ExecuteQuery();